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Photocatalysis technology is one of the potential methods to remit the growing issues of environmental pollution. It is of great significance to rationally design high performance antibiotic wastewater degradation catalysts in the whole pH range. In this experiment, Gd 2 O 3 nanoparticles (GdO NPs) were successfully grown onto CuInZnS (CIZS) by a simple hydrothermal method. The introduction of GdO has obvious effects on the nanosheet thickness of CIZS, which reduces carrier transport distances and improves the active sites number of CIZS. What's more, the SO 4 •- absorption and electron transfer ability are also greatly optimized. Under 300 W Xe light, tetracycline can be efficient degraded more than 93 % in the whole pH range, which presents absolute advantage compared to CIZS and GdO. Based on the combination of experimental characterization and density functional theory calculations, the proposed photocatalytic tetracycline degradation pathway and mechanism have been given. Moreover, the results of toxicity analysis proved that the CIZS-GdO catalyst could successfully reduce the toxicity of tetracycline wastewater. This work has reference value for the application of rare earth oxides in the field of photocatalysis at full pH range. • Gd 2 O 3 nanoparticles (GdO NPs) were successfully grown onto CuInZnS (CIZS) by hydrothermal method. • An efficient photocatalytic degradation of tetracycline at full pH range is achieved. • First-principles calculations and experimental characterizations were combined to study the tetracycline degradation process. • GdO interferes with the nucleation and growth of CIZS, which increases the specific surface area of CIZS. • The SO 4 •- absorption and electron transfer ability are also greatly optimized. [ABSTRACT FROM AUTHOR]

Standard enthalpies of formation at 298.15 K, Δ f H 298. 15 ∘ , for RCoO 3-δ (R = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y) perovskite-type rare-earth cobaltites were obtained from the combined results of drop and reduction calorimetry. The relationship between the oxygen nonstoichiometry, δ, and thermodynamics of RCoO 3-δ was discussed. The fact that RCoO 3-δ with smaller ionic radius of R3+ tend to be less stable, having more positive enthalpy of formation from binary oxides (CoO and R 2 O 3), Δ f , o x H 298. 15 ∘ , was confirmed for all the studied RCoO 3-δ. Drop calorimetry results were also used in discussing, comparing and assessing the literature heat capacity, C p T , data for RCoO 3-δ (R ≠ Y). For YCoO 3-δ , both Δ f H 298. 15 ∘ and C p T were obtained for the first time solely from the drop calorimetric results; Δ f H 298. 15 ∘ values determined by two different methods perfectly agree with each other. The reference data and C p T of RCoO 3-δ were used to calculate Δ f H 298. 15 ∘ from the published EMF measurement results so as to compare the available Δ f , o x H 298. 15 ∘ (RCoO 3-δ) values. An unusual dependence of Δ f H 298. 15 ∘ (LaCoO 3-δ) on its heat treatment history was identified and supported by the additional isoperibolic solution calorimetry measurements. • Enthalpies of formation of several rare-earth cobaltite perovskites were measured. • The primary methods were reduction reaction calorimetry and drop calorimetry. • The implications of non-zero oxygen nonstoichiometry were discussed. • Heat capacity and formation enthalpy of YCoO 3 were measured for the first time. • Enthalpic stability of RCoO 3 is lower when R3+ is smaller (R = rare-earth metal). [ABSTRACT FROM AUTHOR]

In our study, we present comprehensive findings on the structural properties of Pr 2 Ti 2 O 7 across a broad pressure range of 0–30 GPa. Neutron diffraction experiments, conducted under ambient conditions, offer crucial structural insights into the initial monoclinic phase with the P2 1 space group. As pressure increased, a significant phase transition to the monoclinic P2 1 /m phase occurred at 13.8 GPa. Structural data analysis from X-ray diffraction highlights the essence of this transition, identifying it as the tilting of Ti-O 6 octahedra. High-pressure Raman spectroscopy data unequivocally confirms the phase transition, detecting anomalies in the baric dependencies of some vibration modes of Pr 2 Ti 2 O 7 and the emergence of new modes in the Raman spectra within the pressure region associated with the phase transition. The analysis of these novel vibration modes points to alterations in the Ti-O 6 octahedra, emphasizing the pivotal role played by Ti4+ and O2- ions in the mechanism of the pressure-driven phase transition. • Structural and vibration properties of perovskite-like layered Pr 2 Ti 2 O 7 was studied at pressures up to 30 GPa. • The structural phase transition in Pr 2 Ti 2 O 7 was observed at P= 13.8 GPa. • The suppression of the ferroelectric phase of Pr 2 Ti 2 O 7 was discussed. • The bulk modulus of both phases were calculated. [ABSTRACT FROM AUTHOR]

White light emission has long been a focal point of research in the LED field for white lighting. The rare earth element Eu is commonly used as an efficient emission center with various wavelengths in different matrices. In this study, white light emission is achieved by simply adjusting the ratio of Eu3+/Eu2+ in Sr 2 MgSi 2 O 7 phosphor, a phenomenon not observed in previous literature due to the difficulty to realize the photoluminescence of Eu2+ and Eu3+ in a same matrix simultaneously. The targeted Sr 2 MgSi 2 O 7 :9 %Eu fluorescent powder was synthesized under reducing atmosphere conditions, followed by oxidation in an air atmosphere for different durations. The phosphor samples exhibited characteristic Eu3+ and Eu2+ spectra in the XPS results, corresponding to the coexistence of Eu3+ and Eu2+ with varying ratios. The presence of Eu2+ and Eu3+ in the Sr 2 MgSi 2 O 7 matrix leads to white light emission at an optimal Eu2+/Eu3+ ratio. Specifically, the broad emission peak of Eu2+ is located at 460 nm, which is resulted from the transformation from 4 f6 5d1 to 4 f7 for Eu2+ ions and causes a blue light emission. Meanwhile, typical peaks for Eu3+ are detected at 590 nm, 615 nm, 650 nm and 703 nm, corresponding to transitions from the 5D 0 to 7F 1 , 5D 0 to 7F 2 , 5D 0 to 7F 3 and 5D 0 to 7F 4 energy levels in Eu3+ ions, emitting orange-red light. Overall, the Eu3+ and Eu2+ co-doped Sr 2 MgSi 2 O 7 phosphor prepared in our study emits white light under near-ultraviolet excitation, with CIE coordinates of (0.3058, 0.2274), falling within the white region in the CIE color diagram. These results suggest the potential application of the phosphor in the white LED field. • Sr 2 MgSi 2 O 7 :Eu2+, Eu3+ white emitting phosphors were successfully prepared. • Both Eu2+ and Eu3+ show photoluminescence in the silicate matrix. • Eu2+ offers a blue emission peaking at 460 nm due to 4 f6 5d1 to 4 f7 transition. • Eu3+ reveals orange-red emission attributed from 5D 0 to 7F J transition. • White emission was achieved with 9 %Eu: Sr 2 MgSi 2 O 7 by adjusting Eu2+ / Eu3+ ratio. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive investigation into the impact of substituting rare earth elements on the magnetic properties of strontium hexaferrite. The samples, synthesized by the sol-gel Pechini method, followed the formula Sr 1-x Re x Fe 12 O 19 with Re = Gd, Sm, Nd, Pr, and La, for 0.025 ≤ x ≤ 0.100. The findings revealed that Re substitution promotes a considerable increment of the coercive field. However, the magnetic yield dropped with increasing the Re content. Therefore, the higher coercivity field, largest magnetization and maximum energy product (BH max) were reached for samples with x = 0.025. This tendency was consistent across all rare earth-substituted samples although the hexaferrite substituted with samarium and praseodymium showed the strongest hard-magnetic properties. This behavior has been attributed to a reduction of the interaction field due to the emergence of a monodomain structure, and to the limited solubility of rare earth elements within the structure of strontium hexaferrite. • Rare earth substitution in the strontium hexaferrite. • Improvement of the magnetic properties of the strontium hexaferrite. • Effects of Gd, Sm, Nd, Pr and La used as substitution elements in the Sr-M. • Hysteresis properties of the strontium hexaferrite substituted with rare earths. [ABSTRACT FROM AUTHOR]

The problem of low stability and high lead content limit the commercial development of halide perovskite. In this paper, the high-energy ball milling is used to rapidly and efficiently synthesize high-entropy Cs(Pb 1/5 Mn 1/5 Ni 1/5 Zn 1/5 Yb 1/5)Cl 3 quantum dots (QDs), the introduction of high-entropy and rare earth ions reduces lead content, increases mixing entropy, and synergistically enhances the photoluminescence (PL) intensity and stability of QDs with other ions. Because the increase of entropy enhances the stability, the QDs still have 70 % PL intensity after 60 days of placement. After the QDs are exposed to the ultraviolet lamp for 8 hours, the PL intensity maintains at 67.1 % due to the loss of ligand. Ionic bonds are easily broken in water, so after soaking in water for 8 hours, the PL intensity of the QDs keeps at 32 %. The thermal stability of QDs is maintained well because of physical and chemical stability of rare earth ions. Since ethanol dissolves the ligands on the surface of the QDs, the non-radiative recombination is enhanced, so the PL intensity of QDs remains at 59 % after soaking for 8 hours. This paper provides a new way that further enhances the stability and solves high lead content of all-inorganic perovskite materials. • All-inorganic perovskite Cs(Pb 1/5 Mn 1/5 Ni 1/5 Zn 1/5 Yb 1/5)Cl 3 QDs were rapidly synthesized by high-energy ball milling. • The introduction of high-entropy and rare earth ions expands the emission range and enhances the luminous intensity. • The high-entropy QDs show good stability of room temperature, water, high temperature, ultraviolet light and ethanol. [ABSTRACT FROM AUTHOR]

This paper employs the self-propagating high-temperature synthesis (SHS) to prepare Al-Ti-C master alloys and explores the effects of integrating the rare earth element lanthanum to create Al-Ti-C-La composites. This research focuses on the microstructural changes in both the master alloy and pure aluminum, which aimed to elucidate the mechanisms that enhance grain refinement and resistance to grain refinement fading. The analysis reveals that when Al-Ti-C-La master alloys are incorporated into molten Al, the predominant structures formed include an Al matrix, rod-like Al 3 Ti phases, and TiC particles, alongside AlLa phases and substantial Al 20 Ti 2 La compounds. The grain refining capability of Al-Ti-C-La master alloys is significantly exceeds that of the Al-Ti-C master alloys. The addition of La markedly reduces the settling of TiC particles, thereby granting the Al-Ti-C-La master alloys excellent resistance to grain refinement fading. The newly formed Al 20 Ti 2 La phase plays a crucial role in refining the aluminum matrix, with metallic bond characteristics present on the side towards the Al matrix at the Al 20 Ti 2 La/Al interface and distinct covalent bond characteristics on the Al 20 Ti 2 La side. Moreover, the Al 20 Ti 2 La (110)/Al (110) interface exhibits the highest interfacial adhesion energy and stronger covalent bond features. Consequently, α-Al is prone to heterogeneously nucleate on the Al 20 Ti 2 La phase via the Al 20 Ti 2 La (110)/Al (110)-HCP orientation, which refines the grains of the aluminum matrix, ultimately enhancing the performance of aluminum-based alloys. • The study explored the effect of rare earth La addition on the microstructure morphology of Al-Ti-C-La intermetallics. • The refining effectiveness of Al-Ti-C intermetallics on industrial pure aluminum was analyzed, as well as the mechanisms behind refining and fading. • Using the Virtual Crystal Approximation (VCA) method, the Al20Ti2La cell structure was constructed, and the interfacial properties of Al20Ti2La (100)/Al (100), Al20Ti2La (110)/Al(110), and Al20Ti2La (111)/Al (111) under different stacking models were calculated and analyzed. [ABSTRACT FROM AUTHOR]

This study investigated the optical properties of PbO-GeO 2 -Ga 2 O 3 glasses doped with Er3+ and Yb3+ rare earth ions, deposited with gold nanoparticles and annealed at different times (1 h, 12 h, 28 h, and 52 h). By varying the annealing times, we can understand how these thermal processes influence the position of the energy bands, which in turn affects the material's optical properties such as the energy gap and Urbach energy. The study found that the sample annealed for 52 h had the lowest E g value and the highest E u value, indicating significant structural changes due to prolonged thermal treatment. The study aimed to determine the energy gap (E g) and Urbach energy (E U), Judd-Ofelt parameters (Ω 2 , Ω 4 , Ω 6), oscillator strength (f exp and f cal), and root mean square (RMS) deviation. Additionally, the study reports on the linear absorption and heat transfer results, which were used to evaluate temperature changes during Z -scan experiments. The data obtained indicate that the sample subjected to 52-hour annealing has the smallest E g value, suggesting that intense thermal processes and crystallisation affect the positions of the material's energy bands, increasing its ability to absorb light. Consequently, the E U value for this sample is the highest at 0.312 eV, decreasing to 0.203 eV for the sample annealed for 1 h. This indicates that longer annealing times result in more significant structural changes in the glass matrix, thereby modifying its optical properties. The analysis of the obtained results, leads to the conclusion that the lowest values of both experimental (f exp) and calculated (f cal) oscillator strength occur at 546 nm and 811 nm, indicating the potential energy properties of the 4S 3∕2 and 4I 9∕2 levels in the atomic structure. It was observed that the J-O parameters did not exhibit significant changes with increased annealing time, suggesting that short-term thermal processes may be sufficient to achieve a stable energy configuration. This finding is of significant practical importance, as it indicates that the material can maintain its optical properties even with shorter annealing times, thereby enhancing the efficiency of the production process. [Display omitted] • Lowest ( f exp ) and (f cal) values at 546 nm, revealing the crucial role of the 4S 3∕2 energy level. • Short-term annealing achieves stable energy configuration, enhancing practical applicability. • One-hour annealing influences Ω 4 and Ω 2 , impacting specific energy properties. • Intensive thermal processes during 52-hour annealing result in the lowest energy band gap. • Heat transfer variations influenced by absorption coefficients and geometrical differences. [ABSTRACT FROM AUTHOR]

In order to improve the comprehensive hydrogen storage performance of AB 3 -type (RE/Ca)-Mg-Ni alloys, a new series of Ca(Ca0.75La0.25) 2- x Mg x Ni 9 (x = 0.8, 0.9, 1.0, 1.1, 1.2) alloys is designed and prepared. Based on the as-cast Ca 2 MgNi 9 alloy, La is introduced, and the ratio of rare earth (RE) to Mg is adjusted using the induction melting method. This alteration modifies the microstructure of the alloy and significantly enhances its hydrogen storage performance. The effects of microstructure on hydrogen storage performance and mechanism are analyzed. The phase composition and lattice parameters of the main phase are regularly regulated by appropriate element substitution. The lattice parameter of the main phase is increased, the capacity and kinetics of hydrogen storage are significantly improved. The initial hydrogen absorption capacity of the alloy increases from 1.744 wt% for Ca 2 MgNi 9 to 1.975 wt% for Ca(Ca0.75La0.25) 1.2 Mg 0.8 Ni 9 alloy. Furthermore, the synergistic regulation of La and Mg elements can increase the hydrogen desorption ratio and crystal structure stability of the alloy. This leads to the concurrent enhancement of effective hydrogen storage and cycle performance of the Ca 2 MgNi 9 hydrogen storage alloy. The retention rate of hydrogen absorption capacity for the 50th cycle is increased from 77.13% for Ca 2 MgNi 9 to 84.26% for Ca(Ca0.75La0.25) 0.8 Mg 1.2 Ni 9. At the same time, owing to the adjustment of the cell volume and phase composition, the platform pressures of hydrogen absorption and desorption of the alloy have also experienced a multi-fold increase between 0.002 and 0.5 MPa at 303 K. This enhancement is advantageous for expanding the potential applications of this type of alloy. This work presents new ideas for enhancing the hydrogen storage performance of Ca 2 MgNi 9 hydrogen storage alloys. • A new series of Ca(Ca0.75La0.25)2-xMgxNi9 (x = 0.8, 0.9, 1.0, 1.1, 1.2) hydrogen storage alloys is designed. • The activation and the kinetics performance are improved after replacing Ca with a small amount of La. • The effective hydrogen storage and cycling performance are improved by optimizing the ratio of (Ca0.75La0.25)/Mg in the [A2B4] subunit. [ABSTRACT FROM AUTHOR]

The RE 5 Pt 2 In 4 (RE = Gd-Tm) rare earth compounds have been investigated by means of X-ray diffraction (XRD) as well as by DC and AC magnetometric measurements. The compounds crystallize in an orthorhombic crystal structure of the Lu 5 Ni 2 In 4 -type (Pbam space group, No. 55). With decreasing temperature, the intermetallics undergo a transition from para- to ferro-/ferri- (RE = Gd, Tb, Ho, Er) or antiferromagnetic state (RE = Tm). In case of Dy 5 Pt 2 In 4 , the ferromagnetic state is reached through an intermediate antiferromagnetic order present in a limited temperature range. The critical temperatures of magnetic ordering range from 4.1 K (RE = Tm) up to 108 K (RE = Tb). For the majority of investigated compounds, a cascade of additional magnetic transitions is found below the respective critical temperatures of magnetic ordering. The magnetic moments are found solely on the rare earth atoms, while the moments of the remaining Pt and In atoms are absent or are too small to be detected while accompanied by the strong rare earth's moments. The magnetocaloric (MCE) performance of RE 5 T 2 In 4 (RE = Gd-Tm) is found quite good, especially while taking into account the compounds with RE = Ho and Er. Maximum magnetic entropy change (− Δ S M m a x ) reaches 11.8 (RE = Ho) or 11.4 J ⋅ kg−1 ⋅ K−1 (RE = Er) under magnetic flux density change of 0–9 T. Under the same conditions, the relative cooling power (RCP) and refrigerant capacity (RC) equal 607 and 495 J ⋅ kg−1 (RE = Ho) or 434 and 341 J ⋅ kg−1 (RE = Er). • RE 5 Pt 2 In 4 (RE = Gd-Tm) order magnetically at low temperatures. • Magnetic moments are found on the rare-earth atoms which occupy three Wyckoff sites. • The compounds show complex magnetic properties. • A cascade of temperature-induced magnetic transitions is detected. [ABSTRACT FROM AUTHOR]

The self-assembly mechanism of porous materials has always been a hot topic and a challenging issue in research. What factors induce the self-assembly process, and how is the temperature sensing performance related to it? Innovatively, in this paper, Gd 2 O 2 S:Er3+/Yb3+ phosphors with different morphologies were synthesized, and elucidated the formation mechanism of flower-like structures through relevant theorems, formulas, and experiments, proposing that polar molecules and dipole-dipole interactions guide the synergistic effect of van der Waals forces and hydrogen bonding, which ultimately induces the self-assembly of spherical structures into flower-like ones. In addition, four representative intermediates were selected to investigate their luminescence and temperature sensing properties. The results show that the flower-like sample can respond more effectively to changes in ambient temperature because of its rich pore structures, and thus exhibit better temperature sensing performance. In-depth research on the self-assembly mechanism of materials helps to predict and regulate their properties, and the unique characteristics of flower-like sample provide new ideas for material selection in the field of high-precision temperature measurement. • Successfully synthesized flower-like porous Gd 2 O 2 S:Er3+/Yb3+ phosphor for the first time. • The formation mechanism of self-assembly of spherical structures into flower-like structures was deeply investigated. • The up-conversion luminescence and thermometric performance of samples with different morphologies were studied. • The flower-like sample can respond more effectively to temperature changes, with its highest sensitivity reaching 0.089 K−1. [ABSTRACT FROM AUTHOR]

In this work, a series of multicomponent rare-earth zirconate (RE 2 Zr 2 O 7 , RE=La, Nd, Sm, Eu, Gd or Yb) ceramics were synthesized using solid-state reaction method. The phase stability and key factors affecting the thermal conductivity and mechanical performances were investigated. These materials possess pyrochlore-fluorite dual-phase structure and show excellent high-temperature phase stability. (La 1/2 Yb 1/2) 2 Zr 2 O 7 displays a lower amorphous-like thermal conductivity (1.39–1.67 Wm−1K−1, 25–1000 °C), while other specimens present a 1/T-like dependence at low temperatures. (La 1/5 Nd 1/5 Sm 1/5 Gd 1/5 Yb 1/5) 2 Zr 2 O 7 exhibit higher hardness (11.37 ± 0.35 GPa) and fracture toughness (2.10 ± 0.11 MPa·m1/2) in comparison with others. Size disorder shows stronger correlations with the thermal conductivity of multicomponent dual-phase RE 2 Zr 2 O 7 ceramics, while the influence of configurational entropy is more significant for mechanical properties. A synergistic increase in configurational entropy and size disorder is an effective strategy to enhance the comprehensive performance of multicomponent dual-phase rare-earth zirconates. • A series of dual-phase medium- and high-entropy RE 2 Zr 2 O 7 ceramics were tailored and synthesized. • Size disorder shows stronger correlations with the thermal conductivity of multicomponent dual-phase rare-earth zirconates. • Entropy is a more effective descriptor than size disorder for influencing the mechanical properties of these materials. [ABSTRACT FROM AUTHOR]

Due to excellent biological-functionality, unique/suitable elastic-modulus as well as spontaneous degradation behaviors, Mg alloys acted as medical implants have shown enormous potential in surgical operation and bone-fixation fields. Unfortunately, the extreme mass loss and unmarked-fracture could easily induce the implant failure. In the present study, the microstructure characteristics and degradation behaviors of the Mg-10.6Gd-0.3Ag- x (Y/Zn) alloys were investigated through the XRD, TEM, EPMA, XPS, 3D/CLSM and SECM. Results revealed that with the increment of Y/Zn contents, the amount of Mg 24 (Gd/Y) 5 precipitates increased, which were mainly distributed in grains and on grain boundaries. The addition of Zn and Y increased the undercooling and Y had a large mismatch degree with Mg atoms, which could promote the precipitation of second phases. Additionally, the corrosion rates of Mg-10.6Gd-0.3Ag- x (Y/Zn) increased firstly and then reduced. Also, the best corrosion resistance was achieved in the Mg-10.6Gd-0.3Ag-Y-Zn, with the current intensities of 58.49 μA/cm2, attributed to the formation of continuous reticular structure oxide film, which can act as physical barriers and impede the corrosion process. [Display omitted] • Corrosion rate of studied alloys were increased firstly and then reduced. • Y and Zn addition provide nucleation cites to form compact surface protective layer. • The evolution of corrosion current densities was analyzed by SECM. • Y and Zn addition promote the precipitation of Mg 24 (Gd, Y, Zn) 5 phase. [ABSTRACT FROM AUTHOR]

Lanthanide oxides have potential advantages for photocatalytic hydrogen production. To systematically investigate the photocatalytic performance of lanthanide oxides on metal sulfides, a series of Ln x O y /ZnIn 2 S 4 (Ln x O y /ZIS) were synthesized by hydrothermal method. Comprehensive characterization demonstrated that Ln x O y synergistically improved the performance of ZnIn 2 S 4 by extending light absorption, reducing contact interface resistance and enhancing carrier separation. The photocatalytic hydrogen evolution (PHE) rates of the Ln x O y /ZIS photocatalysts were improved, which were 1.6–4.2 times higher than those of pure ZnIn 2 S 4 (198.0 μmol g−1 h−1). The PHE rates of Ln x O y /ZIS decreased with increasing lanthanide atomic number, and when the lanthanides contained variable valence ions, the PHE rates of Ln x O y /ZIS were superior to those of neighbouring lanthanides. The heterojunction formed by Ln x O y and ZnIn 2 S 4 effectively promoted carrier separation. Lanthanide ions with unoccupied 4 f orbital were more likely to accept electrons and served as a hydrogen adsorption site for further hydrogen reduction. Multivalent ions could also promote the migration of electrons and generate oxygen vacancies to inhibit the recombination of carriers. In conclusion, for ZnIn 2 S 4 , lanthanide oxides are promising candidates to improve the performance of PHE. This study provides guidance on the selection of appropriate lanthanide oxides for the construction of efficient sulphur-based heterojunction photocatalysts. [Display omitted] • Ln x O y /ZIS photocatalysts were synthesized through hydrothermal method. • The H 2 evolution rates of Ln x O y /ZIS were 1.6–4.2 times than that of ZIS. • The presence of variable valence ions promoted the formation of oxygen vacancies and excellent carrier separation efficiency. • The 4 f electronic structure of lanthanide ions has an important effect on the photocatalytic hydrogen production activity. [ABSTRACT FROM AUTHOR]

Aiming at the development of thermal environmental barrier coatings (TEBCs) material, the factor of grain size is introduced into the high-entropy rare-earth disilicate for the first time. The (Yb 0.2 Tm 0.2 Lu 0.2 Sc 0.2 Er 0.2) 2 Si 2 O 7 with smaller grain size was prepared by one-step pressureless sintering method. Results of thermal conductivity and coefficient of thermal expansion (CTE) reveal that thermal conductivity of (Yb 0.2 Tm 0.2 Lu 0.2 Sc 0.2 Er 0.2) 2 Si 2 O 7 bulk material is lower than that all existing EBCs and even most TBCs and potential TEBCs material, which is 0.686 W m−1 °C−1 at 1300 °C. Excellent thermophysical properties indicate that designed (Yb 0.2 Tm 0.2 Lu 0.2 Sc 0.2 Er 0.2) 2 Si 2 O 7 with small grain size can be used as a promising TEBCs material. • It is the first time to introduce the grain size into the thermal conductivity of high-entropy rare earth silicate materials. • The prepared (Yb 0.2 Tm 0.2 Lu 0.2 Sc 0.2 Er 0.2) 2 Si 2 O 7 has very low thermal conductivity than all existing EBCs materials. • (Yb 0.2 Tm 0.2 Lu 0.2 Sc 0.2 Er 0.2) 2 Si 2 O 7 with small grain size has excellent thermophysical properties and is a candidate for TEBCs. [ABSTRACT FROM AUTHOR]

The effects of adding Eu3+, Dy3+, and Eu3+/Dy3+ rare-earth elements on the microstructural, optical and electrical properties of lead-free piezoelectric materials based on K 0.5 Na 0.5 NbO 3 (KNN) were investigated. A series of fine powders were synthesized via a modified Pechini route utilizing citric acid. Relatively large amounts of rare-earth elements were successfully incorporated into the crystal lattice of KNN. A combination of X-ray diffraction, X-ray absorption spectroscopy, energy-dispersive X-ray and scanning electron microscopy were used to characterize the structure and chemical composition of the powders and sinters. XRD patterns indicated the formation of a single-phase orthorhombic structure in the co-doped sinter. X-ray absorption spectroscopy revealed the nominal 3+ valence states of Eu and Dy in KNN ceramic sinters. The Mott model and group symmetry theory were used to discuss the characteristics of Raman spectra obtained for the EuDy:KNN ceramics. The ceramics exhibited good dielectric permittivity (ε≃1300) and low dielectric loss (tan δ =0.03) in the temperature range of 170–240°C. The electrical properties of the ceramics showed that the basic mechanism of conduction and relaxation was thermal activation, and that small polaron hopping was responsible for charge carrying. The Eu3+ and Dy3+ ions displayed characteristic red and orange emissions in sinters when excited with light in the wide ultraviolet spectra range (380–420 nm). • Multi-doped KNN-based phosphors can be synthesized via a modified Pechini method. • Co-doped sinters consist entirely of the orthorhombic phase. • It is possible to shift the temperature of phase transitions by doping. • Doping with Eu3+-Dy3+ had a synergistic effect on the dielectric constant. [ABSTRACT FROM AUTHOR]

The low efficiency of conventional liquefaction technologies based on the Joule-Thomson expansion makes liquid hydrogen currently not attractive enough for large-scale energy-related technologies that are important for the transition to a carbon-neutral society. Magnetocaloric hydrogen liquefaction has great potential to achieve higher efficiency and is therefore a crucial enabler for affordable liquid hydrogen. Cost-effective magnetocaloric materials with large magnetic entropy and adiabatic temperature changes in the temperature range of 77 ∼ 20 K under commercially practicable magnetic fields are the foundation for the success of magnetocaloric hydrogen liquefaction. Heavy rare-earth-based magnetocaloric intermetallic compounds generally show excellent magnetocaloric performances, but the heavy rare-earth elements (Gd, Tb, Dy, Ho, Er, and Tm) are highly critical in resources. Yttrium and light rare-earth elements (La, Ce, Pr, and Nd) are relatively abundant, but their alloys generally show less excellent magnetocaloric properties. A dilemma appears: higher performance or lower criticality? In this review, we study how cryogenic temperature influences magnetocaloric performance by first reviewing heavy rare-earth-based intermetallic compounds. Next, we look at light rare-earth-based, "mixed" rare-earth-based, and Gd-based intermetallic compounds with the nature of the phase transition order taken into consideration, and summarize ways to resolve the dilemma. [Display omitted] • A comprehensive review on the magnetocaloric effects of the rare-earth-based intermetallic compounds. • Interpretation of how magnetocaloric properties depend on temperature range of operation. • Summary of methods to tune Curie temperature. • Summary of ways to resolve the dilemma of element criticality and magnetocaloric performance. [ABSTRACT FROM AUTHOR]

With the development of advanced composites, biomaterials have brought the field of tissue engineering and regeneration into a new era. Among them, composites of inorganic nonmetallic materials and rare earth oxides have unique structures and biochemical properties and have attracted widespread interest. In this work, rare earth oxides (CeO 2)/inorganic nonmetallic materials (mesoporous bioactive glass, MBG) composite microspheres (CeO 2 /MBGs) were synthesized by a sol-gel method, and the in vitro biological effect of CeO 2 /MBGs was systematically studied. The filling of CeO 2 /MBGs in irregular bone tumor defects not only promoted osteogenic mineralization in MG63 cells but also had significant antibacterial effects on E. coli and S. aureus. CeO 2 enters the MBG network as a network modifier, while doxorubicin (DOX) is adsorbed into the mesoporous structure through electrostatic interactions, which endows CeO 2 /MBGs with excellent bioactivity and controlled DOX release behavior. Moreover, the results of in vitro experiments showed that the proper addition of rare earth oxides had no toxic effect on normal cells, and the combination of rare earth oxides with antitumor drugs could slow the release of DOX through the use of an intelligent response design system, thus inducing the apoptosis of MG63 cells. This work suggested that combination chemotherapy and the design of a rare earth oxide/MBG composite microspheres may be potential therapeutic approaches for the postoperative repair of bone tumor defects. The construction of this multifunctional rare earth oxide/inorganic biocomposite provides a way to apply the material to bone tissue. [Display omitted] • Systematically describe in vitro biological properties of metal/inorganic composite. • Apoptosis induces on MG63 cell by synergic effect of CeO 2 and DOX. • Metal/inorganic composite exhibited significant antibacterial activity. • Provides a feasible approach on therapeutic for bone tumor defects. [ABSTRACT FROM AUTHOR]

Recently, there have been significant interest in the wide potential of photoluminescence (PL) response of rare-earth doped perovskite oxide thin films in the field of optoelectronics. This work reports an effective method to modulate the PL properties of 0.8 mol%Sm3+-doped BaTiO 3 (BTO:Sm) thin films through static and dynamic strain. BTO:Sm films were epitaxially grown on LaAlO 3 (LAO), 0.7Pb(Mg 1/3 Nb 2/3)O 3 -0.3PbTiO 3 (PMN-PT), MgO, and Mica single-crystal substrates by pulsed laser deposition technique. Compared with the BTO:Sm/PMN-PT heterostructure which experiences minimal lattice mismatch effect, the PL intensity of BTO:Sm/LAO and BTO:Sm/MgO is enhanced by 818.1% and 1014.7%, respectively, due to static tensile/compressive strain (-0.429% and 0.461%) during the epitaxial growth process. In the flexible BTO:Sm/Mica heterostructure, dynamic strain is introduced through mechanical bending. Compared with the unbent state, the u-type and n-type bending modes increase the relative changes in PL intensity (Δ I / I) by 599.0% and 768.5%, respectively. Particularly, BTO:Sm/Mica also exhibits a remarkable optical transmittance exceeding 75% (500–2500 nm). The enhancement of PL intensity is closely related to the adjustment of lattice strain, which changes the crystal field strength of the BTO:Sm and the radiative transition probability. This work provides valuable insights for designing future optoelectronic devices and environmental monitoring equipment. It has the potential to advance photonics and sensor technologies, paving the way for innovation and exploration in these fields. • The enhancement of PL intensity in BTO:Sm thin films is achieved through static strain. • High-quality BTO:Sm thin film with high transmittance and low roughness is epitaxially grown on Mica substrates. • Dynamic tuning of the PL behavior in BTO:Sm thin film is achieved by applying bending induced dynamic strain. [ABSTRACT FROM AUTHOR]

Neodymium (Nd) magnets are in high demand for use in the manufacture of electric vehicle motors and medical equipment such as magnetic resonance imaging. In this study, we describe a new process for recycling Nd permanent magnets (PMs). PM scrap powder was leached into a waste pickling solution, evaporated under reduced pressure, concentrated, and converted into an oxide via heat treatment. Nd was selectively leached from the prepared oxide using hydrochloric acid. Iron was removed from the leached solution, and the Nd composite was then recovered using a urea-mediated Nd-recovery method. The oxidation temperature was determined using a thermogravimetric analysis. High-purity Nd-oxide powders were obtained by calcination at 900 °C. This economical process enables the recovery of PM powder by relying on the pickling process and acid-regeneration plants, which are both essential in steel manufacturing. [Display omitted] • The feasible technology for recycling waste permanent magnets is demonstrated, applicable in steel industry. • Waste pickling solutions are used for leaching out waste permanent magnet. • High purity Nd composites are recovered by urea-mediated pH adjustment route. • Nd oxide is obtained through heat treatment and the crystallinity of phase is confirmed via Rietveld refinement. [ABSTRACT FROM AUTHOR]

This study provided the first in-depth investigation of the effects of large dopant incompatibility (Pr3+ and La3+ ions) on the small host lattice element (Lu3+) in Lu 3 Al 5 O 12 (LuAG) single crystal. The growth of such complex crystals from the melt presented many challenges. By engineering the ionic radius ratio of RE- and M-site cations, a single-crystal phase stabilized by configurational entropy was achieved. This investigation elucidated the crystallization behavior of configurationally disordered rare-earth aluminum garnet oxide (Lu 1−x−y Pr x La y) 3 Al 5 O 12 from the melt and characterized its functional properties, including microstructural, optical, photoluminescence, and scintillation properties, between 5 and 300 K. Relaxation of the imposed strain energy led to local perturbations and destabilization of the garnet structure. Multielemental EDS mapping, micro-Raman spectroscopy, and thermoluminescence revealed the mechanism by which atomic size mismatch drove a smooth transition from the garnet to the perovskite phase in high entropy garnets. The optical, photoluminescence, and scintillation measurements provided fundamental insights into property changes driven by incompatibility doping. Standard and modified Judd-Ofelt theory analysis of absorption spectra determined the phenomenological Judd-Ofelt parameters Ω λ and radiative lifetimes. Atomic size mismatch engineering offers a promising approach to overcoming the limitations of conventional eutectic synthesis methods. • Perovskite inclusions, driven by atomic size mismatch, extend from rim to core. • Controlled incompatible La3+,Pr3+ codoping in LuAG modify functional properties. • Scintillation light yield improved up to 30% in La3+ codoped LuAG:Pr crystals. • (La,Pr)AlO 3 perovskite forms due to size mismatch of La3+ and Pr3+ with Lu3+. • Lattice disorder affects the intensity ratio of Pr³⁺ 5d→4 f and 4 f→4 f emissions. [ABSTRACT FROM AUTHOR]

In this work, we studied the effects of rare earth ytterbium (Yb) doping on the structure and ultraviolet (UV) emission properties of MgZnO films deposited by magnetron sputtering and subsequent high-temperature annealing. For the samples with low and medium Mg content, the UV photoluminescence (PL) and cathodoluminescence (CL) increased considerably by the Yb doping, while for the samples with higher Mg content they decreased. X-ray diffraction indicates the formation of MgZnO nanocrystals in the samples, together with the formation of Mg- and Zn- silicates, as well as the formation of Yb silicates and Yb 2 O 3 after the Yb doping. The surface morphologies of the samples are sensitive to the Mg content and the Yb doping level as observed by scanning electron microscopy. The UV–visible absorption spectra show that the optical bandgap of the samples with medium/or higher Mg content, both increase slightly by the Yb doping. The PL decay spectra indicate that the lifetime of the UV PL increases with Yb doping for the samples with low content of Mg, while decreases for the samples with high Mg content. The results demonstrate that UV emissions are closely related to the film quality after the Yb doping. This work may be useful to broaden the UV emission of ZnO-based materials in the UV photonics. • The UV emissions in photoluminescence from MgZnO films on Si can be enhanced significantly by the Yb doping for low/medium content of Mg. • The intensity of the UV emission from MgZnO films is closely related the crystalline quality of the MgZnO film. • MgZnO nanocrystals as well as Zn-and Mg-silicates, and Yb silicates -oxides form in the films upon heat treatment (700 -1000 °C). • The optical bandgap of MgZnO samples with medium or higher Mg content, increases by Yb doping according to Tauc-analysis. [ABSTRACT FROM AUTHOR]

Heavy rare-earth A 2 Zr 2 O 7 zirconates have been studied for their high application potential, including thermal barrier coating, radiation waste storage, or solid oxide fuel cells. However, previous investigations have focused mostly on the high-temperature properties of polycrystalline samples. The low-temperature properties, important for a full understanding of these materials, remains understudied. We have newly synthesised good-quality single crystals of A 2 Zr 2 O 7 with A = Er, Tm, Yb, and Lu using the laser heated pedestal method and have characterised them by means of X-ray diffraction, magnetisation, and specific heat measurements. The first three members crystallise in a cubic disordered defect-fluorite structure. Lu 2 Zr 2 O 7 adopts lower-symmetry rhombohedral structure. Similar magnetic properties of all magnetic zirconates were observed at low temperature. In the unperturbed paramagnetic state, they follow the Curie-Weiss law with an effective magnetic moment close to the respective A 3+ free ions. The negative paramagnetic Curie-Weiss temperature, in the case of A = Yb member highly negative, strongly suggests an antiferromagnetic ordering in the compounds. Below 30 K, the magnetic response becomes non-linear in the applied magnetic field, suggesting magnetic correlations between rare-earth moments or/and crystal field effects. Finally, at lowest measured temperature, Er 2 Zr 2 O 7 and Yb 2 Zr 2 O 7 members reveal a well-pronounced anomaly in specific heat at 0.9 and 1.5 K, respectively. The specific heat anomaly shifts to higher temperature in an applied magnetic field, suggesting ferromagnetic correlations – in contradiction to the negative Curie-Weiss temperature. We discuss these observations in the framework of freezing of magnetic moments on a disordered geometrically frustrated lattice. In contrast, the low-temperature properties of Tm 2 Zr 2 O 7 are dictated mostly by its crystal electric field; a crystal-field-singlet ground state which does not provide degrees of freedom for a spin-freezing is proposed. No clear low-temperature anomaly in specific heat is observed down to 0.4 K for the A = Tm member. Lu 2 Zr 2 O 7 does not bear any magnetic moment, therefore no magnetic signal was observed in any measured data. The results are discussed in the framework of heavy rare-earth A 2 B 2 O 7 oxides and other magnetically frustrated systems. • Good-quality Er 2 Zr 2 O 7 , Tm 2 Zr 2 O 7 , Yb 2 Zr 2 O 7 , and Lu 2 Zr 2 O 7 single crystals were synthesised. • Tm 2 Zr 2 O 7 single crystal was synthesised for the first time using laser heated pedestal method. • Low-temperature properties of Tm 2 Zr 2 O 7 are fully determined by crystal field effects. • Short-range correlations and strong magnetic frustration were observed in Er and Yb members. • Lattice disorder-induced dynamic magnetic ground state is proposed in these zirconates. [ABSTRACT FROM AUTHOR]

LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) high-nickel lithium layered oxide material has gained recognition as a promising cathode material for lithium-ion batteries (LIBs) due to its relatively high output capacity. However, the presence of high nickel content leads to capacity fading resulting from surface residue lithium and cathode-electrolyte interfacial side reactions, posing a significant threat to the cycle life for battery. In this study, we have developed an ultrathin and uniform CeO 2 &LiCeO 2 nanoscale rare earth composite functional coating in-situ for NCM811 cathode, utilizing residual lithium and rare earth oxide. Ex-situ scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectrometer (XPS) analyses confirm the reduction in interfacial side reactions, leading to improved stability at the cathode-electrolyte interface. This improvement can be attributed to the removal of surface residual lithium and the formation of stable CeO 2 &LiCeO 2 functional coatings. As a result, the NCM811 modified with the rare earth composite functional coating exhibits a higher capacity retention rate after 100 cycles (90.9% vs. 86.1%) and enhanced rate capacity (136 mAh g−1 vs. 117 mAh g−1) at 5 C than the NCM811. Even the designed full battery achieves an energy density as high as 253 Wh kg−1. This work presents an innovative approach to utilize residual lithium and rare earth oxide for in-situ functional coating formation, ultimately enhancing the lithium storage performance of high-nickel NCM811 cathodes. [Display omitted] • In-situ reaction utilization of surface residual lithium and rare earth oxides. • An ultrathin and uniform CeO 2 &LiCeO 2 rare earth composite functional coating. • The stability of the electrode electrolyte interface is greatly improved. • A high-nickel NCM811 cathode with excellent lithium storage performance. [ABSTRACT FROM AUTHOR]

Different electronic structure on 4 f shell endows rare earth with variable of catalytic activity. In order to explore the catalytic effect of rare earth on solid oxide fuel cell (SOFC) electrode, we prepare electrolyte-supported (Sr 1.8 Ln 0.2)FeMoO 6 /SDC/LSGM/SBCO single cell with Ln = Sr, La, Sm and Eu, and investigate their electrochemical performance based on X-ray diffraction (XRD), DC four-point probe, I-V and electrochemical impedance spectra. XRD results show that (Sr 1.8 Ln 0.2)FeMoO 6 are of single phase and belong to I4/m space group. Owing to the increased density of states, electronic conductivity of (Sr 1.8 La 0.2)FeMoO 6 (SLFM), (Sr 1.8 Sm 0.2)FeMoO 6 (SSFM) and (Sr 1.8 Eu 0.2)FeMoO 6 (SEFM) increases significantly, where SEFM exhibits the highest value in the measuring range. The higher conductivity and the smaller activation energy favor the power output of the investigated cell. The maximum power density of Sr 2 FeMoO 6 (SFMO)-based cell is 772 mW·cm−2 at 850 ℃, that of SLFM- and SSFM-based cell increases to 890.8 mW·cm−2 and 861.6 mW·cm−2, while SEFM-based cell exhibits the highest value of 964.6 mW·cm−2. Electrochemical Impedance Spectroscopy (EIS) finds that SEFM-based cell possesses the smallest electrode resistance, charge transfer resistance, the fastest surface exchange and oxygen diffusion process, which favors its highest power output. These results demonstrate that the synergistic reaction in catalytic activity between rare earth atoms and SFMO lattice is different to a large degree, and our innovative discovery is the good catalytic activity of SEFM anode, which is conducive to comprehensively understanding the catalytic properties of rare earth for SOFC electrodes. • The synergy in catalytic activity between rare earth and Sr 2 FeMoO 6 is different to a large degree. • (Sr 1.8 Eu 0.2)FeMoO 6 exhibits the highest conductivity. • (Sr 1.8 Eu 0.2)FeMoO 6 -based cell depicts the best electrochemical performance. [ABSTRACT FROM AUTHOR]

In the process of strengthening the substrate's surface properties, it is easy to produce cracks or air holes and other defects between the coatings and the substrate, and rare earth elements can improve the microstructure and properties of the metal surface coatings. Using laser cladding(LC) technology, the effect of the addition of rare earth oxides CeO 2 on the properties of AlCoCrFeNi 2.1 coatings is investigated to find the optimal amount of CeO 2 added. AlCoCrFeNi 2.1 alloy powder doped with Xwt% (X = 0–3) rare-earth oxide CeO2 was clad on the surface of the H13 steel substrate by laser cladding process using RFL-C3000 laser. The macroscopic morphology, microstructure, hardness, and corrosion resistance of specimens were analyzed and studied by optical microscope (OM), scanning electron microscope (SEM), X-ray diffractometer (XRD), hardness tester, and other equipment. The results show that the addition of the appropriate amount of rare earth oxide CeO 2 (3 %) can effectively reduce the cracks, air holes, and inclusions in the composite layer, and promote grain refinement. The addition of 3 wt%CeO 2 to AlCoCrFeNi 2.1 can improve the microstructure uniformity and surface hardness of the coatings, and significantly improve the wear and corrosion resistance of the composite coatings. • AlCoCrFeNi 2.1 high-entropy alloy coatings with added CeO 2 were prepared by laser cladding. • The increase of CeO 2 content refines the grains and produces lattice distortion. • The high-entropy alloy coatings with added CeO 2 have better-forming quality, uniform microstructure, and composition. • The CeO 2 -added high-entropy alloy coating has high hardness, wear resistance, corrosion resistance. [ABSTRACT FROM AUTHOR]

Four kinds of high-entropy oxides (HEOs) with compositions of Y 0.2 Zr 0.2 Hf 0.2 Ce 0.2 X 0.2 O 2−δ (X = La, Nd, Gd, Dy, abbreviated as HEO-La, Nd, Gd, Dy, respectively) are synthesized by solid-state-reaction method combined with conventional sintering in air atmosphere at 1600 °C for 10 h. These HEOs have a fluorite-structured phase with homogeneous element distribution. The thermal conductivity (κ) of these four samples is in 1.68–2.18 W m−1 K−1 in 25–900 °C. At 800 °C and 900 °C, the κ value of HEO-Gd is lower than those of the HEO-La, Nd, Dy, yttria-stabilized zirconia (YSZ) and some other HEOs with various crystal structures ((Gd 0.2 Dy 0.2 Ho 0.2 Er 0.2 Tm 0.2)Ta 3 O 9 , (La 0.25 Eu 0.25 Gd 0.25 Yb 0.25) 2 Zr 2 O 7 , (Sm 0.2 Dy 0.2 Ho 0.2 Er 0.2 Yb 0.2)NbO 4 , Hf 0.25 Zr 0.25 Ce 0.25 Gd 0.125 Ca 0.125 O 2-δ and Sr(Y 0.2 Sm 0.2 Gd 0.2 Dy 0.2 Yb 0.2) 2 O 4). The sample of HEO-Gd has the highest thermal expansion coefficient (CTE) (12.1 × 10−6 K−1) and fracture toughness (K IC) (2.5 MPa m1/2) among HEO-La, Nd, Gd, Dy. Its K IC value is higher than those of other HEOs mentioned above. In addition, HEO-Gd exhibits a better oxygen barrier property compared with YSZ in 450–700 °C. These results indicate that HEO-Gd is a promising candidate as high-temperature thermal insulation ceramic. • HEO-La, Nd, Gd, Dy have a fluorite-structured phase. • HEO-Gd exhibits low thermal conductivity and high fracture toughness. • HEO-La, Nd, Gd, Dy show a superior oxygen barrier property than YSZ. [ABSTRACT FROM AUTHOR]

To attain superior electrochemical performance, a new series of high-entropy double perovskites are investigated as cathodes for solid oxide fuel cells. In this study, three PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5 double perovskites with different dopings of La, Pr, Sm, Gd, Nd, Y elements in A-site, high-entropy oxides (HEOs) cathodes are successfully prepared by EDTA-citrate combustion method and used as potential cathodes for SOFC at intermediate temperature. Three HEOs cathodes all form single phase double perovskite structure and match chemically well with Gd 0.2 Ce 0.8 O 2-δ (GDC) electrolyte. Linear thermal expansion coefficient of (La 0.2 Pr 0.2 Sm 0.2 Gd 0.2 Nd 0.2)Ba 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5 (LPSGNBSCF) at 200–1000 °C range is found to be moderate, 18.39 × 10−6 K−1. Typical anode supported SOFC with LPSGNBSCF cathode exhibits an excellent output performance of 1000 mW cm−2 with a lower polarization resistance of 0.3 Ω cm2 at 800 °C. These results might suggest that LPSGNBSCF can be a potential excellent cathode for SOFC. • High entropy PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ cathodes with A-site dopings are prepared. • SOFC with LPSFNBSCF cathode exhibits output performance of 1000 mW cm−2 at 800 °C. • LPSGNBSCF can be a potential cathode for SOFC. [ABSTRACT FROM AUTHOR]

Yttrium iron garnet (YIG) crystals are the primary candidate for non-reciprocal device. With the miniaturization and integration of optical communication devices, the modified YIG crystals with excellent comprehensive performances are highly desired. To explore the possible mechanism of rare earth ions doping on Faraday effect, holmium oxide-doped YIG (Ho 0.6 Y 2.4 Fe 5 O 12 , abbreviated as HYIG) crystal was grown by molten salt method. Its structure, optical transparency, magnetic, magneto-optical properties and oxygen atmosphere annealing processes were first investigated systematically. The HYIG crystal wafers annealed at 800 °C for 2 h can achieve the large Faraday rotation angle (186 deg/cm at 1310 nm; 148 deg/cm at 1550 nm) and good optical transparency (73.64 % at 1310 nm; 74.83 % at 1550 nm), which is increased by approximately 10 % compared to the unannealed sample. This result may provide a new insight into the investigation of rare earth doped YIG crystals and their atmosphere annealing processes. [Display omitted] • Centimeter-size HYIG crystal with Ho3+ doping was grown by the TSSG method. • The content of oxygen vacancy and Fe2+ ion decreased after annealing. • The transmittance and Faraday rotation angle are increased by about 10 % after annealing at 800 °C. [ABSTRACT FROM AUTHOR]

Due to the limited temperature capability of widely used yttria partially stabilized zirconia (YSZ), considerable effort has been directed towards developing promising thermal barrier coating materials for applications above 1200 °C. La 2 O 3 -Gd 2 O 3 -Yb 2 O 3 -Y 2 O 3 -doped zirconia (LGYYSZ), as a promising ceramic for advanced thermal barrier coatings, was designed and prepared. The LGYYSZ ceramics consist of tetragonal double-prime phase and cubic phase, and no new phase appears after long-term annealing. The thermal expansion coefficients of LGYYSZ are comparable to the value of YSZ. The values of the thermal conductivities of 0.5LGYYSZ and 1.0LGYYSZ are 1.34 W/(mK) and 1.21 W/(mK) at 1000 °C, respectively, which are approximately 30–40% lower than that of YSZ. Due to the rare earth ions with different radii/masses and the compound effect of multiple point dislocations, a significant improvement of the sintering resistance of LGYYSZ ceramics was observed above 1400 °C with La3+ dopant. • Ternary rare earth doped YSZ (LGYYSZ) are mainly cubic phase and contains a small amount of t" phase. • Multiple point defects in LGYYSZ strength phase stability and the thermal conductivities decreased with increasing of La 2 O 3. • La3+ expand the tetrahedron which contains oxygen vacancy, and thus a little increase in the thermal expansion coefficient. • Doped ions affect stability of defects, the densification and sintering process were suppressed. [ABSTRACT FROM AUTHOR]

This work is devoted to a simple method for synthesizing phosphors based on layered rare earth hydroxonitrates (LRH). Layered precursors of (Y 0.95 Eu 0.05) 2 (OH) 5 (NO 3)· x H 2 O with different morphologies were obtained via co-precipitation at a constant pH and hydrothermal methods. It was established that LRHs co-precipitated at pH 7 are highly ordered close-packed micron-sized plates with low porosity. With an increase in the pH of co-precipitation to 9.5, the phase composition is retained, but the isotropy and porosity of the particles increases sharply: the morphology changes from micron flat plates to curved nanosheets and nanoflakes. Co-precipitated LRHs crystallize more intensively into cubic (Y 0.95 Eu 0.05) 2 O 3 during heat treatment compared to precursors obtained under mild hydrothermal conditions (120 °C, 24 h). The structural characteristics of the material laid at the stage of synthesis directly determine its optical properties and the fundamental parameters of photoluminescence. The phosphors that co-precipitate at pH 7 demonstrate the highest yield of luminescence due to a more ordered structure, larger crystallite size, lower asymmetry factor and surface to volume ratio. The proposed co-precipitation method with a constant pH value of 7 allows one to obtain (Y 0.95 Eu 0.05) 2 O 3 phosphor with enhanced structural and optical properties compared to materials synthesized in hydrothermal conditions. The LRHs co-precipitated in this work are a promising precursor for the preparation of crystal-oriented and highly-efficient luminescent coatings and nanofilms. Image 1 • Co-precipitation at low pH causes oriented growth of layered rare-earth hydroxides. • Oriented growth form ordered plates with larger crystallite size and low surface. • The calcined phosphors inherit the morphology of the precursors. • Oxide phosphors from the plate-like particles show the highest luminescence yield. [ABSTRACT FROM AUTHOR]

The ceramics based on the Y 2 O 3 -ZrO 2 system is promising for development of refractory materials including ultra-high temperature ceramics. In the present study the samples of the Y 2 O 3 -ZrO 2 system were synthesized by the solid-state method. The vaporization processes and thermodynamic properties of the Y 2 O 3 -ZrO 2 system were studied by the Knudsen effusion mass spectrometric method. The vapor composition, the YO, ZrO, ZrO 2 and O partial pressures over the samples as well as the Y 2 O 3 and ZrO 2 activities of the Y 2 O 3 -ZrO 2 system were determined at the temperature 2660 K. Thermodynamic properties (i.e. excess Gibbs energies) of the Y 2 O 3 -ZrO 2 system obtained in the present study can be described in terms of the subregular solution model. • Vaporization and thermodynamics of Y 2 O 3 -ZrO 2 system at 2660 K were studied by KEMS. • Consistency of component activities was confirmed by modified Redlich-Kister approach. • Negative deviations from ideality were observed in this system. [ABSTRACT FROM AUTHOR]

Erbium doped tin-oxide thin film transistors (ErSnO-TFTs) were fabricated by Radio-Frequency magnetron sputtering (RFMS) using SnO target and Er foil. Effects of Er concentration on crystallinity, optical band-gap, surface chemical information, defect states, surface morphology, along with the electrical properties of ErSnO-TFTs, were investigated. The results indicate that moderate Er concentration is beneficial to the performance of ErSnO-TFTs. The relatively good device performance was obtained at the Er concentration of 3.1 at.% within our experimental conditions. The optimum field-effect mobility (μ FE), subthreshold swing (SS), threshold voltage (V th), on-off current ratio (I on/off) and the total interfacial trap states (N t) are 3.9 cm2/V, 0.49 Vdec−1, -0.4 V, 2.9 × 107 and 5.1 × 1011 cm−2. This work may pave the way for the development of lanthanides doped Sn-based thin film devices. Image 1 • Novel In-free Er-doped SnO 2 thin film transistors were fabricated. • ErSnO-TFTs exhibit a good combination property. • Lanthanide oxides exhibit a potential in the application of SnO 2 -based TFTs. [ABSTRACT FROM AUTHOR]

Abstract Two new structural types of BaREGeO 4 (OH) and BaRE 10 (GeO 4) 4 O 8 (RE = Ho3+,Er3+) single crystals were synthesized via high-temperature and high-pressure hydrothermal synthesis. The BaREGeO 4 (OH) compounds were found to crystallize in the orthorhombic space group Pbca. BaHoGeO 4 (OH) is used as a representative of the family with cell parameters of a = 5.7175(2) Å, b = 10.1556(5) Å, c = 10.6189(9) Å and V = 964.97(8) Å3. The BaREGeO 4 (OH) structure contains a one-dimensional chain of rare-earth polyhedra linked through edge sharing of oxygen atoms. High density BaRE 10 (GeO 4) 4 O 8 crystals crystallize in the monoclinic space group C 2/ m and feature a sheet like arrangement of rare-earth oxide polyhedra with Keggin-like features. BaHo 10 (GeO 4) 4 O 8 is used as a representative of this structure type with cell parameters of a = 12.4533(8) Å, b = 7.2008(5) Å, c = 12.0034(8) Å, β = 100.183(2)⁰ and V = 1059.43(12) Å3. Barium polyhedra and isolated GeO 4 units aid in connecting the rare earth oxide framework to extend it in three-dimensional (3-D) space. Characterization by single crystal X-ray diffraction and Raman and photoluminescence spectroscopies is reported. Graphical abstract Image 1 Highlights • BaREGeO 4 (OH) and BaRE 10 (GeO 4) 4 O 8 (RE = Ho, Er) were synthesized. • The compounds are structurally characterized, and are new structure types. • Single crystals over 2 mm in diameter were grown. • Characterization by Raman and photoluminescence spectroscopies is reported. [ABSTRACT FROM AUTHOR]

Abstract Nowadays, trivalent rare-earth ions activated inorganic luminescent materials have been widely investigated owing to their important applications in solid-state lighting field. Tm3+ and Dy3+ ions single- or co-doped Ba 3 La 6 (SiO 4) 6 (BLSO) phosphor materials for white light application were synthesized by a citrate-based sol-gel method. The prepared samples were examined by X-ray diffraction (XRD), scanning electron microscopy and Fourier-transform infrared spectroscopy to analyze the phase purity, surface morphology and existence of functional groups, respectively. The XRD pattern confirmed that the BLSO host lattice exhibited a hexagonal crystal structure with P 6 3 / m (176) space group, which is well indexed with standard JCPDS data. From photoluminescence results, the BLSO:Tm3+ phosphors exhibited purplish blue emission at 453 nm (1D 2 →3F 4) and the BLSO:Dy3+ phosphors showed predominant yellow emission at 575 nm (4F 9/2 → 6H 13/2) compared to their shoulder blue emission at 479 nm (4F 9/2 → 6H 15/2), indicating that the Dy3+ ions occupied lattice sites with low inversion symmetry. The determined Commission Internationale de I'Eclairage (CIE) (0.3391, 0.3302) values for the Tm3+/Dy3+ co-doped BLSO phosphors were near to the standard sun light CIE values (0.33, 0.33) under near-ultraviolet (364 nm) excitation. The energy transfer process from Dy3+ to Tm3+ ions was discussed and it was proved by their corresponding decay curves. Additionally, thermal study was carried out for the optimized phosphor and it maintained superior thermal PL properties. Graphical abstract Image 1 Highlights • Ba 3 La 6 (SiO 4) 6 :Tm3+/Dy3+ phosphors were synthesized by a sol-gel method. • The structural properties of Ba 3 La 6 (SiO 4) 6 host lattice were studied. • The co-doped phosphors showed efficient white-light CIE values (0.3391, 0.3302) under NUV (364 nm) excitation. • The optimized co-doped BLSO phosphors exhibited excellent thermal stability. [ABSTRACT FROM AUTHOR]

Abstract Annealing temperature-dependent ultrathin Dy 2 O 3 gate dielectric films, grown on Si substrates by reactive sputtering, were characterized in terms of structural, optical and electrical properties using x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), UV–Vis transmission spectroscopy and electrical measurements of Dy 2 O 3 /Si gate stack. Additionally, the thickness of the interfacial SiO 2 layer during the deposition and annealing process has been calculated using the Si 2p XPS spectra to exclude its influence on the electrical parameter of Dy 2 O 3 films. XPS analyses for all the samples have shown the abrupt growth of the Dy-silicate for 700°C-annealed sample, which is identified as the primary reason for the dramatic reduction in its electrical performance. In addition, optimized Dy 2 O 3 sample with annealed temperature at 600 °C exhibits the lowest equivalent oxide thickness of 1.6 nm, the highest dielectric constant 16.8, the lower leakage current density 4.45 × 10−8 A/cm2 and the lower frequency dispersion of 6.21%. Based on the experimental analysis, the optimized annealing temperature has been obtained to achieve Dy 2 O 3 gate dielectric thin films as deposition of high-k with high-quality on Si substrates. Graphical abstract Image 1 Highlights • Sputtering-derived Dy 2 O 3 gate dielectrics were deposited on Si substrates. • 600 °C-annealed Dy 2 O 3 films exhibit excellent electrical performance. • Rare-earth-based high-k dielectric demonstrates potential application in CMOS device. [ABSTRACT FROM AUTHOR]

Abstract The new type of Al-Ti-C-La master alloy was prepared by commercial pure Al, Ti powder, graphite powder, Al powder and La 2 O 3 powder by aluminum melt in-situ reaction method. The microstructure and the effect on commercial pure aluminum of Al-Ti-C-La master alloy have been studied by means of X-ray diffraction (XDR), scanning electron microscopy (SEM) equipped with energy-dispersive spectrometry (EDS). The synthesis thermodynamics and kinetics of Al-Ti-C-La master alloy were analyzed. The experiment shows that Al-Ti-C-La master alloy is composed of Al, Al 3 Ti, TiC and Ti 2 Al 20 La. The refining performance of the prepared Al-Ti-C-La master alloy is obviously better than that of Al-Ti-C master alloy when the addition of rare earth oxide La 2 O 3 is 10 wt% and the preparation temperature is 930 °C. The analysis of thermodynamic calculation and the process of kinetics demonstrate that, in the preparation process of Al-Ti-C-La master alloy, firstly, Al reacts with Ti to produce Al 3 Ti, C reacts with Ti and Al 3 Ti to form TiC based on the aluminothermy reaction. Rare earth oxide La 2 O 3 and C powder react with Ti powder and O 2 in the air occur to generate CO, TiC, [La] atoms and LaC 2. [La] atoms adsorb on the surface of Al 3 Ti to form the new rare earth compounds Ti 2 Al 20 La. Highlights • Al-Ti-C-La master alloy was prepared while structure of the master alloy was studied. • Thermodynamics was calculated in the preparation process of Al-Ti-C-La master. • A kinetic model of the synthesis reaction of Al-Ti-C-La master alloy was established. • The refinement mechanism of Al-Ti-C-RE master alloy was analyzed. • Adding La 2 O 3 contributes to the refining performance of Al-Ti-C-La master alloy. [ABSTRACT FROM AUTHOR]

The rapid capacity fading of the Ni-rich cathode has become the main obstacle to its development. Generally, the coating method can be used for modification, which can effectively isolate side reactions and maintain the original structure. In this study, novel rare earth (La, Ho, Tm) polymetallic oxide (REPMO) coating is topologically prepared on the surface of LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) by using high speed shearing with reduction method. After modification, the high-rate capacity at 5 C enhanced a lot (100.3 mA h g−1 vs 31.2 mA h g−1) which is 3.2 times higher. This is because the Ni2+ of the cathode could be changed into Ni3+ to reduce the mixing of Li+/Ni2+ and the structural stability has been improved. Moreover, the synergistic effect of REPMO coating can increase ionic conductivity, accelerate Li+ diffusion rate and inhibit the phase transition, cation mixing and volume shrinkage. Our work provides an innovative idea at this moment for the selection and synthesis method of coating material for modification of cathode material. • Novel rare earth polymetallic oxide coating is prepared on NCM811 by surface topological conversion process. • The rare earth polymetallic oxides can increase the diffusion coefficient of lithium ions and improve the rate performance. • The rare earth polymetallic oxide can weaken the volume shrinkage of lattice and enhance the stability of cycle performance. [ABSTRACT FROM AUTHOR]

Recently, rare earth oxide has attracted much attention because of its widely applications in petroleum, chemical engineering, metallurgy, ceramics etc. Among them, ceria has been considered as an important additive to improve metal's corrosion resistance. In this study, CeO 2 modified SiO 2 was prepared as additive in electrodeposition of Zn-Ni coating. The state of the as-prepared particles was characterized. The structure and wettability as well as the microhardness of coatings were tested. Moreover, the corrosion performance of coatings was analyzed in detail by means of potentiodynamic polarization technique and electrochemical impedance spectrum (EIS) in 3.5 wt % NaCl solution which used as corrosion medium. The results show that the particles disperse well among the coatings. The morphology of the coating presents a dense structure and keeps a highly preferred orientation. Meanwhile, the coating with CeO 2 modified SiO 2 exhibits much better corrosion resistance properties compared with that of both Zn-Ni and Zn-Ni-SiO 2 coatings. The corrosion current density of the prepared coating was remarkably decreased with two and one orders of magnitude compared with those two CeO 2 -free coatings mentioned above, respectively. The introduction of CeO 2 also significantly increases the coating's electrochemical impedance. The corrosion mechanism of the above three types of coating on low carbon steel were analyzed and discussed based on two different equivalent circuit models respectively. [ABSTRACT FROM AUTHOR]

Secondary aluminium dross has been widely generated due to the extensive development of the secondary aluminium industry. In this study, reutilization of secondary aluminium dross and the effect of rare earth oxides (REO) doping on the MgAl 2 O 4 were studied. The results showed that secondary aluminium dross can be used to produce MgAl 2 O 4 spinel, and that the densification behaviour of the spinel can be improved by doping with Y 2 O 3 , Eu 2 O 3 , La 2 O 3 , and CeO 2 . The densification of doped MgAl 2 O 4 was higher than that of MgAl 2 O 4 without REO in the temperature ranged from 1473 to 1773 K. Especially, the density of the spinel with 3 wt% La 2 O 3 at 1673 K for 3 h was 2.13 g cm −3 . The improvement of the spinel densification was attributed to the solubility of rare earth ion and the formation of liquid phases such as YAlO 3 , Y 2 Ti 2 O 7 , Ca 2 Eu 8 (SiO 4 ) 6 O 2 , Al 2 Ca 0.5 La 0.5 , and CeO 2 . The results suggested that the secondary aluminium dross doping with REO for the MgAl 2 O 4 spinel can be broadened its reutilization. [ABSTRACT FROM AUTHOR]

The performance of Y 2 O 3 nanocrystals with three distinct sizes, doped with 2 mol% of Er 3+ ions, as nanothermometers, exploiting two different methodologies is investigated. We found that the sensitivity of the temperature sensor using such crystals is high and this magnitude depends strongly on the crystallite size. For nanothermometers based on fluorescence intensity ratio (FIR) from thermally coupled levels ( 2 H 11/2 , 4 S 3/2 ), the sensitivity is higher for larger nanocrystals. On the other hand, when using FIR from levels which are not thermally coupled ( 2 H 11/2 , 4 F 9/2 ), highest sensitivities were obtained for the smaller nanocrystals. Moreover, the values of absolute and relative sensitivities measured for these samples are among the highest reported so far in literature. These results indicate that Er 3+ -doped Y 2 O 3 nanocrystals are promising materials for temperature sensing in nanoscale and that the choice of nanocrystals' size and FIR methodology may improve the sensing performance aiming a specific application. [ABSTRACT FROM AUTHOR]

In order to improve the activation behavior of Ti 1.02 Cr 1.1 Mn 0.3 Fe 0.6 alloy with high hydrogen desorption pressure for hybrid hydrogen storage vessel application, the rare earth (RE) doped Ti 1.02 Cr 1.1 Mn 0.3 Fe 0.6 RE 0.03 (RE = La, Ce, Ho) alloys were prepared by induction levitation melting. The effect of rare earth doping on the microstructures and hydrogen storage properties was also investigated systematically. The results show that Ti 1.02 Cr 1.1 Mn 0.3 Fe 0.6 alloy displays a single C14 Laves phase, and there is a secondary phase of rare earth oxide in the RE doped alloys. The RE doping strategy can expand the unit cell volume of C14 Laves main phase. After RE doping, the activation behavior of the Ti 1.02 Cr 1.1 Mn 0.3 Fe 0.6 RE 0.03 alloy is obviously improved and the hydrogen storage capacity is increased, while the hydrogen desorption plateau pressure is decreased. Moreover, the RE-free alloy can hardly absorb hydrogen at room temperature under 34–43 MPa hydrogen pressure, but all RE-doped alloys can absorb hydrogen to saturation under the same condition. The decline of pressure plateau is inversely proportional to the atomic number of RE. Among the studied alloys, the Ti 1.02 Cr 1.1 Mn 0.3 Fe 0.6 La 0.03 alloy shows the best overall properties and can be fully activated at room temperature. Its hydrogen absorption pressure is 39.31 MPa and 51.27 MPa under 298 K and 318 K, respectively. Its hydrogen storage capacity is up to 1.715 wt% and the dissociation enthalpy is 16.63 kJ/mol H 2 with a desorption plateau slope of 0.098. [ABSTRACT FROM AUTHOR]

In this study, effects of rare earth oxide CeO 2 and Y 2 O 3 on the structure and properties of glass-diamond composites were systematically researched. The thermal analysis of the borosilicate glass was performed by TG-DSC curves. Phase composition of the glass-diamond composites was analyzed by XRD. SEM images showed the microstructure of the composites. Thermal properties of the composites were characterized by thermal conductivity and coefficient of thermal expansion. Bending strength was measured to explain the mechanical properties. Results showed that the addition of CeO 2 and Y 2 O 3 improved the mechanical and thermal properties of the glass-diamond composites and CeO 2 /Y 2 O 3 compound additive had greater impacts on the composites than single additive. When the content of CeO 2 /Y 2 O 3 additive reached 4 wt % (1.07 vol %), the thermal conductivity and bending strength of the glass-diamond composites increased by 69.77% and 35.13%, respectively. [ABSTRACT FROM AUTHOR]

The Ni60 alloy cladding layers added with La 2 O 3 , Y 2 O 3 , CeO 2 were prepared on the surface of 6063Al using laser cladding technology. The effects of rare-earth oxides on the microstructure, hardness, friction and wear properties of laser cladding Ni-based coating were investigated by XRD, SEM, microhardness tester, friction and wear tester. The results showed that, the main phase composition of the cladding layers is β-NiAl (Cr), Al 3 Ni, AlNi 3 and Al, and the Ni60 cladding layers added rare-earth oxides will produce chemical reaction that involved in the cladding process to form stable rare-earth compounds. Compared with Ni60 cladding layer without rare-earth, the micro-morphology of the Ni60 cladding layers added with La 2 O 3 , Y 2 O 3 and CeO 2 respectively are preferable, which are more smooth and without obvious pores and cracks. The dendritic structures of Ni60 cladding layers are coarse, and there are many grain segregation in the local area, accompanied by a large number of pores, while the organization of Ni60 cladding layers added with rare-earth oxides are compact dendrite, and the grain are obviously refined. The hardness of the cladding layers from the surface to the substrate is gradually decreased with increasing depth of the cladding layer. Compared with Ni60 cladding layer without rare-earth, the wear properties of Ni60 cladding layers added with rare-earth La 2 O 3 , Y 2 O 3 and CeO 2 respectively are improved. [ABSTRACT FROM AUTHOR]

In this paper, the modification and strengthening dual functionality of rare-earth oxide is authenticated by the effect La 2 O 3 /BaO on composition-structure-property correlations of new type La 2 O 3 -BaO-SiO 2 (LBS) glass-ceramics sealing material with high softening point, high coefficient of thermal expansion and excellent high temperature resistivity. As the network modifier, the La 2 O 3 can create more non-bridging oxygen than the BaO, resulting in the increase of Q0 and Q1 units and the decrease of Q2 and Q3 units in the La 2 O 3 -BaO-SiO 2 glass according to Raman and 29Si Solid-State Nuclear Magnetic Resonance. The strengthening functionality of La 2 O 3 is declared by Static 139La WURST-QCPMG NMR spectra that La3+ ions form La-O bonds with O2- ions in the glass structure and La3+ spectra widens slightly with the increasing of La 2 O 3. Correspondingly, physical properties including Tg, Tc, ρ, and M V of La 2 O 3 -BaO-SiO 2 glass gradually increase with increasment of effective cation field strength. The main crystal phase of LBS glass-ceramic transforms from Ba 2 Si 3 O 8 to Ba 5 Si 8 O 21 and furthur to Ba 3 Si 5 O 13 phase with high coefficient of thermal expansion and there is not lanthanum-contained phase precipitation. The coefficients of thermal expansion (CTE) of LBS glass-ceramic increases from 12.48 × 10−6/℃ to 13.18 × 10−6/℃ (30–1000 ℃) and the softening temperature are between 1231.1 ℃ and 1305.1 ℃. The direct-current (DC) resistivity of the LBS glass-ceramics is higher 106 Ω·cm at a high temperature of 700 °C, which has good high-temperature electrical insulation. All in all, the high CTE, high Ts and high electrical insulation "Tri-high" properties of rare-earth oxide La 2 O 3 -BaO-SiO 2 glass-ceramic will be an excellent candidate for solid oxide fuel cell, solid oxide electrolysis cell, oxygen sensors, and so on. • The modification and strengthening dual function of rare-earth oxide is authenticated by the La 2 O 3 -BaO-SiO 2 glass sealant. • The La 2 O 3 creates non-bridging oxygen and the La3+ ions form La-O bonds with O2- ions in the glass structure. • The main phase of LBS glass changes from Ba 2 Si 3 O 8 to Ba 5 Si 8 O 21 , further to Ba 3 Si 5 O 13. • The CTE and Ts of the sealant are higher 12 × 10−6/℃ (30–1000℃) and 1200℃, respectively. • The DC resistivity of all LBS glass-ceramics is higher 10 6Ω·cm at 700°C. [ABSTRACT FROM AUTHOR]

LiFePO 4 cathode material has sluggish Li-ion diffusivity, which largely depends on surface modification to accelerate its slow kinetic process. Metal oxides, such as Al 2 O 3 , are promising coating materials to improve the capacity retention of the cathode materials in lithium-ion batteries, but their improvement on the diffusion rate of Li-ion is limited. In order to obtain the lithium iron phosphate cathode material with excellent rate and cyclic stability, this paper uses the advantages of La 2 O 3 which has both good stability and low lithium ion diffusion barrier to prepare LiFePO 4 /C@La 2 O 3 by a simple and easy operation method. The cathode of LiFePO 4 /C@La 2 O 3 shows high lithium ion diffusivity of 1.4982 × 10−13 and decreased interface impedance by calculating the Li+ diffusion coefficient and measuring conductivity. Furthermore, the LiFePO 4 /C@La 2 O 3 exhibits excellent rate capacibility (126 mAh g−1 at 10 C within 2.4–4.2 V) and long-cycle stability (96.5% capacity retention at 1 C after 500 cycles). These results indicate that further research on these oxide coating materials can enlarge the applicability of these materials. [Display omitted] • Lanthanum oxides has been applied as coating layer to improve the electrochemical properties of LiFePO 4 cathode. • The cathode of LiFePO 4 /C@La 2 O 3 exhibits an excellent rate capability of 126 mAh g−1 at 10 C within 2.4–4.2 V. • The cathode of LiFePO 4 /C@La 2 O 3 displays long-cycle stability of 96.5% capacity retention at 1 C after 500 cycles. [ABSTRACT FROM AUTHOR]

High entropy oxides (HEOs) with 5 or more cations in equimolar proportions that result in a phase-pure material, are a new class of materials attracting a lot of attention in recent years. HEOs exhibit interesting optical, electrochemical, magnetic and catalytic properties. To get a comprehensive understanding of the physics behind the complex interactions taking place in these materials, it is important to evaluate the material in (near-fully) dense forms, such as pellets or thin films. The fluorite structured high entropy oxide, (CeLaSmPrY)O 2−x has been investigated only in the powder form and there are no studies on the dense form of fluorite (CeLaSmPrY)O 2−x. One of the main reasons is that (CeLaSmPrY)O 2−x undergoes a structural transition from fluorite to bixbyite (at 1000 °C) and typically temperatures above the transition (>1200 °C) are required for achieving high densities via conventional sintering. In this study, we synthesize dense films of fluorite structured (CeLaSmPrY)O 2−x by sol-gel as well as pulsed laser deposition processes. The films synthesized via sol-gel process exhibit equiaxed grains and polycrystalline morphology, whereas columnar and epitaxial films are obtained using pulsed laser deposition. Thus, microstructural tuning of dense fluorite (CeLaSmPrY)O 2−x films has been demonstrated while maintaining the basic characteristics of the HEO as observed in the powder form, therefore, paving the way towards more comprehensive studies for possible applications. • Dense thin films of fluorite structured rare earth based high entropy oxide (Ce,La,Sm,Pr,Y)O are synthesized. • Pulsed laser deposition and sol gel process are utilized to synthesize the films. • Films with equiaxed polycrystalline, columnar and epitaxial microstructures are achieved. • Oxidation states and band gaps observed are similar to that of the values observed in powder form. [ABSTRACT FROM AUTHOR]

Structural stability and phase transitions in mixed rare earth sesquioxides (Eu 1− x Ho x ) 2 O 3 crystallizing in the cubic bixbyite structure were investigated under high pressure using angle dispersive X-ray diffraction technique. Studies on various compositions of the mixed oxide show that when the average cationic radius, R RE (where, R RE = x R Ho +(1− x )R Eu ) is equivalent to or below 0.9164 Å, the system undergoes a cubic to monoclinic transition as a function of pressure, whereas, when R RE equivalent to or above 0.9220 Å it is observed to prefer a transition from cubic to hexagonal structure. Based on our detailed investigations, a pressure-concentration (P− x ) phase diagram for (Eu 1− x Ho x ) 2 O 3 up to a pressure of 15 GPa is constructed. The bulk moduli for the parent and high pressure phases are calculated from the Birch-Murnaghan equation of state fit to the experimental pressure volume data and are reported. Structural analysis based on refinement has revealed that, an increasing structural rigidity of the cubic phase with decreasing R RE leads to an increase in the transition pressure and bulk moduli except for 0.4 ≤ x ≤ 0.6. The observed significant reduction in bulk moduli and transition pressure for 0.4 ≤ x ≤ 0.6 is due to the increased micro strain/internal pressure developed upon doping. [ABSTRACT FROM AUTHOR]

Double perovskite R 2 CoMnO 6 systems, with magnetically active rare earth (R) elements, have attracted much attention because of their interesting field sensitive magnetic phenomena and remarkable physical properties. The perovskite compound Gd 2 CoMnO 6 exhibits a field-induced metamagnetic phase transition from ferrimagnetic to long range ferromagnetic (FM) ordering below a critical temperature of T C ∼112 K. It also shows polarization of the Co/Mn magnetic sublattice to the Gd moments resulting in antiferromagnetic (AFM) like behaviour at T N ∼47 K. Further, the large change in magnetization at low temperatures of T < 10 K originates from the single ion Gd 3+ excitations. A sharp peak at T C in AC susceptibility measurements reveals that susceptibility is the sum of the true critical maximum and Hopkinson peak contributions. Below T N ∼47 K, the 4 f -3 d negative exchange interaction is responsible for the observed antiferromagnetic spin polarizations; consequently the exchange bias (EB) effect originates from the unidirectional anisotropy induced at the antiferromagnetic/ferromagnetic interface. [ABSTRACT FROM AUTHOR]

In this paper, work function and dry sliding wear behavior of the hardfacing alloys with different content of nano rare earth oxides (REOs) were studied. The microstructural changes of the hardfacing alloys with and without nano REOs were observed. The integral work function of hardfacing alloys was measured by Scanning Kelvin Probe. The individual work function of the constituent phases was indirectly measured and compared by Atomic Force Microscope. Pin-on-disc wear testing machine was used to conduct dry sliding wear tests. The results showed that nano REOs changed the volume fractions of primary carbide, eutectic carbide and the matrix. Nano REOs increased the integral work function of hardfacing alloys by increasing the volume fraction of primary carbide with high work function. The work functions of primary carbide and eutectic carbide were similar, which were higher than that of the matrix. Nano REOs improved the wear resistance of hardfacing alloys. The variation trends of friction coefficient and integral work function with the content of nano REOs were reversed. The variation trends of wear rate and integral work function with the content of nano REOs were also reversed. The hardfacing alloy having higher integral work function had better wear resistance. [ABSTRACT FROM AUTHOR]