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Pure NiO, BaFe12O19, and Ni0.5Zn0.5Fe2O4 nanoparticles were synthesized by the co-precipitation method. Four ternary (1 − x–y)NiO/xNi0.5Zn0.5Fe2O4/yBaFe12O19 (x and y between 0 and 1) nanocomposites (NCs) were prepared by the wet ball milling technique, then calcined at 950 °C for 4 h. The X-ray powder diffraction (XRD) validated the production of pure NiO and Ni0.5Zn0.5Fe2O4 without impurities, while BaFe12O19 was produced with the α-Fe2O3 additional phase. When compared to the initial weight percentages, the Rietveld refinement technique revealed different weight percentages for the three phases. The transmission electron microscope (TEM) and the selected area electron diffraction (SAED) investigated the morphology and the microstructure of the samples, respectively. X-ray photoelectron spectroscopy (XPS) showed that nanocomposites were successfully formed from the examination of the elements constituting the nanocomposites (Ba2+, Ni2+, Ni3+, Zn2+, Fe3+and O2−). The vibrating sample magnetometer (VSM) measurements identified the effect of the weight percentage of each phase in the nanocomposite on the magnetic parameters. The switching field distribution (SFD) curves indicated significant exchange coupling interactions in the samples that include a small weight percentage of BaFe12O19. Exchange and dipolar interactions were both recognized in Henkel plots of all samples, although exchange coupling predominated. Four laws of approach to saturation (LAS) were applied to the samples and showed magnetization dependency on H−1 and H−1/2 rather than the summation of H−1, H−2, and H for almost all samples. [ABSTRACT FROM AUTHOR]

Nanocomposites of (Mg0.9Ni0.1O)x/(CoFe2O4)1-x, with 0 ≤ x ≤ 1 in weight fractions, were synthesized through the co-precipitation method followed by high-speed ball milling. The investigation of the structural, optical, and magnetic properties was conducted for the synthesized samples. X-ray diffraction (XRD) analysis confirmed the formation of CoFe2O4 and Mg0.9Ni0.1O distinct phases in the nanocomposites without any detectable impurities or minor phases. Transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) revealed the presence of spherical particles in both the individual phases and their nanocomposites. Raman spectroscopy exhibited strong, well-defined modes for CoFe2O4, indicating its spinel phase formation, while Mg0.9Ni0.1O displayed two broad peaks (G and D bands). X-ray photoelectron spectroscopy (XPS) was utilized to analyze the elemental compositions and oxidation states (Co2+, Fe2+, Fe3+, Mg2+, Ni2+, and O2−). The magnetic measurements revealed the soft ferromagnetic behavior of pure cobalt ferrite and a combination of weak ferromagnetism and paramagnetic behavior at high magnetic fields for pure Mg0.9Ni0.1O. [ABSTRACT FROM AUTHOR]

The structural, mechanical, optical, and magnetic properties of RE3+ (Nd3+and Sm3+) doped cadmium zinc ferrites were investigated. The purpose of the rare-earth dopants is to deduce the possible applications for the prepared samples. The Cd0.5Zn0.5RExFe2-xO4 ferrite (x = 0.00, 0.01, 0.08) was synthesized using the wet chemical co-precipitation method. The structural investigations were done using X-ray diffraction (XRD) fitted using Rietveld refinement. The analysis confirmed the spinel structure's crystallinity belonging to the Fd3m space group. The cation distribution and many other structural parameters were estimated from the XRD data. Cation distribution calculations were done using a custom-built Python program that proved the normal structure of the prepared ferrites. The mechanical properties were calculated using the data extracted from Fourier transform infrared (FTIR) spectra, which showed an increase in porosity, weakening of elastic moduli, increase in ionic distances, and expansion of the unit cell. The optical properties were studied using Photoluminescence (PL) spectroscopy and Ultraviolet–Visible (UV–Vis) spectroscopy, which allowed the evaluation of the energy gaps that are found to range between 3.24 and 3.27 eV for the direct energy gap. The results confirmed the quantum confinement effect due to the decrease of crystallite size with the increase of the energy band gap. Optical analysis also showed that the prepared ferrites are good candidates for optoelectronics and nonlinear optical applications. Mössbauer spectroscopy and vibrating sample magnetometer (VSM) investigate the magnetic and structural properties that verified the superparamagnetic behavior in all samples. [ABSTRACT FROM AUTHOR]

This study examined the impact of adding hard ferrite Ba0.5Sr0.5Fe12O19 (BSF) nanoparticles to the Bi1.8Pb0.4Sr2Ca2Cu3.2O10+δ (Bi, Pb)-2223) superconductor phase. The investigation specifically focused on evaluating the critical current density, fluctuation-induced conductivity, and magnetoresistance of nano-(BSF)x/(Bi, Pb)-2223 composite, where 0.00 ≤ x ≤ 0.20 wt.%. The results revealed that the critical current density, Jc, increased with the addition of nano-(BSF) up to x = 0.04 wt.%, reaching a value of 441.20 A/cm2. The Aslamazov and Larkin (A–L) approach has been evaluated the fluctuation-induced conductivity. Several superconducting parameters, including coherence length ζc(0), effective layer thickness d, penetration depth λpd(0), and Fermi energy E F showed improvement as the concentration of nano-(BSF) increased up to x = 0.04 wt.%. In addition to Ginzburg–Landau critical parameters, such as the thermodynamic critical field Bc(0), lower critical magnetic field Bc1(0), upper critical magnetic field Bc2(0), and critical current density Jc(0) demonstrated an increase up to x = 0.04 wt.%, followed by a decrease for higher concentrations. The magnetoresistance measurements were performed at various applied DC magnetic fields, with values ranging from 0.29 to 4.44 kG, and were analyzed using the thermally activated flux creep (TAFC) and Ambegaokar–Halperin (AH) models. The calculated flux pinning energy (U) increased with the addition of nano-(BSF) up to x = 0.04 wt.% and then decreased for x > 0.04 wt.%. Furthermore, the transition width (ΔT), was observed to increase as the applied magnetic field values increased. Moreover, the addition of nano-(BSF) increased the field-independent critical current density, Jc,0(0), up to x = 0.04 wt.%, after which it decreased for higher concentrations. [ABSTRACT FROM AUTHOR]

The effect of samarium and lanthanum fluorides (SmF3 and LaF3) on the structural and superconducting properties of Tl0.8Hg0.2Ba2Ca2−xRxCu3O9-δ-yFy superconducting phase (Tl, Hg)-1223, where R = Sm or La and x = 0.00, 0.025, 0.050, 0.075, and 0.10 was investigated. The solid-state reaction method was used to synthesize the superconducting samples. The phase formation percentages and lattice parameters were calculated using X-ray powder diffraction (XRD). Images taken with a scanning electron microscope (SEM) show that the presence of both Sm and La increases the grain size and inter-grain connectivity up to x=0.025. The successful substitution of Sm and La elements in the crystal structure of (Tl, Hg)-1223 is confirmed by energy-dispersive X-ray (EDX) analysis. The oxidation states of the elements in the prepared samples are revealed by X-ray photoelectron spectroscopy (XPS) spectra. I–V and resistivity measurements were used to investigate the electrical properties of the (Tl, Hg)-1223 system with Sm and La substitutions. The superconducting transition temperature (Tc) and transport critical current density (Jc) have steadily improved up to x = 0.025, above which they dropped significantly. Furthermore, as temperature increased, the temperature dependence of fluctuation conductivity (Δσ), revealed distinct zones. The zero-temperature coherence length (ξc(0)), effective layer thickness of the two-dimensional system (d), interlayer coupling (I), Fermi velocity (vf), and Fermi energy (Ef) were determined. ξc(0) and d decrease until x= 0.025, then increase as x increases. All estimated I values show weak coupling between CuO2 planes and a transition from three-dimensional (3D) to two-dimensional (2D) regions. [ABSTRACT FROM AUTHOR]

This report investigates the effect of La doping on the structural, microstructural, magnetic, thermodynamic, and mechanical properties of Mg1/3Ni1/3Co1/3Fe2-xLaxO4 (x = 0.00, 0.02, and 0.08) spinel ferrites prepared via the wet co-precipitation method. The prepared samples attained a single cubic ferrite phase; except for the pure sample, additional minor traces of hematite secondary phase were formed. The La3+ dopants influenced the expansion of the lattice from 8.351 to 8.372 Å and the reduction of the crystallite size from 30.21 to 14.02 nm, as the dopant concentration increased from zero to x = 0.08. The morphology of the samples depicted highly agglomerated spherical nanoparticles, in which the agglomeration increased with the doping concentration due to the magnetic interaction and size effects. The local physical properties were investigated using Mössbauer spectrometry analysis at 300 K and 77 K by measuring the isomer shift, the quadrupolar shift, and the hyperfine field. The appearance of sextet peaks was registered for all the samples, accompanied by a paramagnetic doublet for x = 0.08 sample at 300 K. Moreover, the La3+ dopants enhance the lattice distortion due to the mismatch of their ionic radii with Fe3+ ions, causing a decrease in the hyperfine field from 46.9 to 26.0 T, at 300 K. The elemental composition, valence, and cationic distribution were investigated using X-ray photoelectric spectroscopy (XPS). The results showed a migration of Fe3+ ions from octahedral to tetrahedral sites upon La doping, which was matched by Mössbauer and XPS measurements. Additionally, Fourier transform infrared spectroscopy was employed to determine the force constants, elasticity, energy, thermodynamic, and mechanical parameters. The La dopants have enhanced the elastic moduli by 11% and the Debye temperature by 4% with x = 0.08 concentration. The Vickers microhardness measurements showed a reverse indentation size effect of the prepared samples, assured by Meyer’s rule. Also, it is revealed that La3+ dopants have boosted the Vickers microhardness, as it increased from 6.951 to 7.520 GPa, as La3+ concentration increased from zero to x = 0.08. This enhancement was correlated to the grain size reduction, following the Hall–Petch relation. These findings suggest the usage of the synthesized La-doped tri-ferrites for industrial applications. [ABSTRACT FROM AUTHOR]

The goal behind this study is to find out the effect of adding nanoscale graphene oxide (GO) on the microstructural, electrical, and mechanical properties of polycrystalline Bi1.6Pb0.4Sr1.9Ca1.1Cu2.1Oy; (Bi, Pb)-2212 superconductor. The solid-state reaction was used to synthesis the (GO)x/Bi1.6Pb0.4Sr1.9Ca1.1Cu2.1Oy, with x = 0.0, 0.1, 0.4, 0.8, 1.0, and 2.0 wt%. The prepared samples were characterized using X-ray diffraction, Scanning Electron Microscope, energy-dispersive X-ray, and Fourier Transform Infrared spectroscopy. The results confirm the formation of (Bi, Pb)-2212 superconducting phase with a volume fraction ranging between 87.51 and 81.43%, respectively. Four probe-technique was used to run the electrical resistivity-temperature variation from room temperature down to zero-resistivity temperature (T0) from which the superconducting transition temperature (Tc) was evaluated. X-ray Photoelectron spectroscopy was used to probe the electronic properties of samples and explain the variation of superconducting parameters. The result shows the dependence on the favored replacement of Pb2+ ions in the Bi3+ or Cu2+ sites caused by differences in the oxygen content conveyed by the addition of GO. The mechanical properties of the synthetized composites were investigated via the Vickers microhardness (Hv) test, at different applied loads and dwell times. These measurements indicated that all samples followed the “indentation size effect” (ISE) behavior. The indentation-induced cracking (IIC) model showed the optimal fitting at low and high load regions. The calculated stress component revealed that, in all samples, the indentation creep mechanism is the grain boundary sliding. [ABSTRACT FROM AUTHOR]

(BaFe12O19)1 − x/(MgO)x nanocomposites, with weight fraction x = 0, 0.1, 0.2, 0.4, 0.8 and 1, have been synthesized by co-precipitation method followed by high-speed ball-milling techniques. Structural, optical, and magnetic properties have been studied. XRD analysis confirmed the formation of the two pure phases BaFe12O19 and MgO, with the formation of a MgFe2O4 as a minor phase in the nanocomposites. Transmission electron microscopy (TEM) followed by high resolution TEM and SAED were used to study the morphology, crystallinity and lattice spacing, respectively. TEM micrographs revealed the co-existence of spherical and nanorod-shaped particles for pure BaFe12O19, and cubic shape for MgO nanoparticles. Raman spectrum for BaFe12O18 showed strong and sharp modes, identifying the formation of barium hexaferrite phase. However, MgO showed two broad peaks attributed to G and D bands. The energy dispersive X-ray and scanning electron microscope were performed for elemental analysis and surface topography, respectively. The real elemental compositions matched well with the starting values. X-ray photoelectron spectroscopy was conducted for the investigation of the elemental compositions and the oxidation states of (Ba2+, Fe2+, Fe3+ Mg2+ and O2−). The magnetic properties like saturation magnetization, remanent magnetization, coercivity and squareness ratio have been determined using the M–H loops. These loops revealed the hard ferromagnetic behavior of pure barium hexaferrite and the mixture of ferromagnetism with diamagnetic behavior at high fields for pure MgO. The saturation and remanent magnetizations decreased with the addition of MgO phase. dM/dH curves showed a weak magnetic coupling between the hard magnetic BaFe12O19 and the soft magnetic MgFe2O4. [ABSTRACT FROM AUTHOR]

In this study, lanthanum La-doped Mg0.33Ni0.33Co0.33Fe2-xLaxO4 (0.00 ≤ x ≤ 0.08) nanoferrites were synthesized using the co-precipitation method. The physical properties of the samples were examined using X-ray diffraction (XRD), transmission electron microscope (TEM), selected area electron diffraction (SAED), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy and vibrating sample magnetometer (VSM). The XRD results confirmed the formation of a single-phase spinel ferrite. Upon increasing the La3+ ions concentration, crystallite and particle sizes decreased as revealed from XRD and TEM analysis, respectively. The values of the lattice parameter estimated from the SAED are in harmony with those obtained from XRD patterns. The appearance of two bands in the FTIR spectra, mainly in the range of 592–595 and 387–422 cm−1, confirms the formation of the spinel structure. Furthermore, the red shift in A1g Raman mode, observed in La-doped nanoferrites, was attributed to the active motion of Fe3+ towards the A sites. The samples demonstrated a ferromagnetic behavior with a reducing saturation magnetization from 31.87 to 12.99 emu/g as x increased from 0.00 to 0.08, respectively. Different forms of the law of approach to saturation (LAS) were employed to fit M–H hysteresis curves of experimental data. Moreover, different parameters were investigated, including the exchange field, anisotropy field, Bohr magneton, and magnetocrystalline anisotropy. These parameters were further analyzed to check the accuracy of the fitting and the best-suited model. [ABSTRACT FROM AUTHOR]

In this study, the impact of adding samarium iron garnet (Sm3Fe5O12; SmIG) nanoparticles to the (Bi1.6Pb0.4)Sr1.9Ca0.9Y0.2Cu2.1O8+δ ((Bi, Pb)-2212) superconductor was investigated. The conventional solid-state reaction method was utilized to synthesize (SmIG)x(Bi, Pb)-2212 phase with different concentrations (x = 0, 0.25, 0.5, 0.75, 1, and 2 wt%). The structure, the morphology, and the elemental composition were tested using X-ray powder diffraction spectroscopy (XRD), scanning electron microscopy (SEM), and dispersive X-ray spectroscopy (EDX), respectively. Filling of pores and voids validated the impact of the added nano-SmIG on intergrain connections. The enhancement in oxygen content was verified by iodometric titration analysis. The superconducting transition temperature (Tc) and the critical current density (Jc) showed best enhancement with the addition of nano-SmIG up to x = 0.75 wt%, having values of 91.02 K and 373.95 A/cm2, respectively. The fluctuations in the superconducting properties were explained via X-ray photoelectron spectroscopy (XPS) by studying the elemental composition and oxidation states for all elements. Vickers microhardness (Hv) investigations were carried out at different applied loads and indentation time of 20 s, where Hv reached its highest value at x = 0.25 wt%. Based on Hv values, the modified proportional sample resistance (MPSR) model offered the most suitable theoretical model to elucidate the experimental data. [ABSTRACT FROM AUTHOR]

In the present study, the synthesis, using the wet co-precipitation method, and characterization of Mg 1 / 3 Ni 1 / 3 Co 1 / 3 Fe 2 - x Gd x O 4 , with x = 0.00, 0.02 and 0.08 wt% nanoparticles were reported. The X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) confirm the formation of nano-spinel ferrite. The crystallite size of Mg 1 / 3 Ni 1 / 3 Co 1 / 3 Fe 2 - x Gd x O 4 nanoparticles decreased, resulting from the microstrain induced by Gd3+ substitution. However, the lattice parameter "a" increased, in agreement with the difference between the ionic radii of Fe3+ and Gd3+ ions. X-ray photoelectric spectroscopy (XPS) measurements were conducted to verify the elemental composition, valency, and cationic distribution. Furthermore, Fourier-Transform Infrared spectroscopy (FTIR) was used in combination with XPS to estimate the force constants, elasticity parameters, and Debye temperature. Vickers microhardness measurements were carried out to investigate the mechanical behavior of the prepared samples and determine Young's modulus. The values of Young's modulus obtained from the microhardness measurements are larger than those obtained from FTIR measurements. However, the results, obtained from both techniques, showed an enhancement with Gd3+ doping. [ABSTRACT FROM AUTHOR]

Objectives: Loneliness functionally varies and is determined by the degree of interaction with others. We examined weekly fluctuations in reported loneliness as a function of frequency of social interactions in old age. We hypothesized that emotional and social components of loneliness would be related to different types of social relationships. Design: Participants reported their feeling of loneliness and their social interaction quantity (frequency of meetings) via a weekly based diary, over 6 weeks. Setting: Diary study. Participants: The study included 55 older adults with different dwelling arrangements (M = 73.4, SD = 6.97). Measurements: Measures of Loneliness (the De Jong-Gierveld Loneliness Scale), Social Interaction and Contact , and sociodemographic parameters were used. Results: Social and emotional loneliness fluctuated over the course of the 6-week study. Frequency of meeting friends was related to emotional loneliness and total feelings of loneliness. Frequency of meeting close/trusted figures was related to emotional loneliness which appeared the following week. Other variables were not associated with either changes in loneliness or its dimensions. Conclusions: Loneliness in old age is changeable. The emotional component of loneliness seems to be dominant in determining overall feelings of loneliness and is more sensitive to externally chosen social interaction. [ABSTRACT FROM AUTHOR]

The structural properties of (x)CuO/(1-x)CdFe2O4 nanocomposites for x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5 and 1.0 were studied. The X-ray diffraction (XRD) patterns confirmed the existence of both phases with a secondary phase of α-Fe2O3. The Fourier-transform infrared spectroscopy (FTIR) characterization showed the vibrational bands of the synthesized samples. The high resolution transmission electron microscopy (HRTEM) micrographs revealed the presence of CuO, CdFe2O4, and α-Fe2O3 phases and showed the polycrystalline nature of the prepared nanocomposites. The scanning electron microscope (SEM) study exhibited the morphology of the prepared nanostructures and indicated the agglomeration between them. The energy-dispersive X-ray spectroscopy (EDX) results revealed the presence of all chemical elements within the synthesized nanocomposites. Emission peaks of the samples were analyzed via Photoluminescence (PL) deconvolutions which approved the interface defects. The Mössbauer study showed the presence of hematite impurity and the results were coherent with XRD findings. The obtained M-H loops from the vibrating-sample magnetometer (VSM) analysis depicted a paramagnetic nature of CuO and showed the ferromagnetic behavior of the nanocomposites. [ABSTRACT FROM AUTHOR]

To manifest the effect of hard magnetic Ba0.5Sr0.5Fe12O19 nanoparticles on the mechanical performance of the (Bi,Pb)-2223 superconducting phase, nano-(Ba0.5Sr0.5Fe12O19)x/Bi1.8Pb0.4Sr2Ca2Cu3.2O10+δ, with x = 0.00, 0.01, 0.02, 0.03, 0.04, 0.05, 0.10, and 0.20 wt%, were synthesized using a conventional solid-state reaction method. The X-ray diffraction (XRD) data revealed that adding nano-(Ba0.5Sr0.5Fe12O19) to the host (Bi,Pb)-2223 phase preserved the orthorhombic structure. The porosity (P%) calculations revealed a decrease until x = 0.04 wt%, which suggests that the addition of nano-(Ba0.5Sr0.5Fe12O19)x reduces the number of voids and improves inter-grain connections, as confirmed by SEM micrographs. The superconducting transition temperature (Tc) increased to 112 K with the inclusion of nano-(Ba0.5Sr0.5Fe12O19) up to x = 0.04 wt%. Vickers microhardness (HV) measurements were conducted at various applied loads (0.245–9.800 N) and a duration time of 45 s. The HV number increased with the addition of x up to x = 0.04 wt% but then decreased with further addition. Various models were employed for analysis and modelling of Vickers hardness (HV) versus test load (F), including Meyer's law, Hays–Kendall (H–K) model, the elastic/plastic deformation (EPD) model, the proportional sample resistance (PSR) model, the modified proportional sample resistance (MPSR), and indentation-induced cracking (IIC) model. It was found that the PSR model was the most appropriate theoretical model for describing the microhardness of nano-(Ba0.5Sr0.5Fe12O19)x/(Bi,Pb)-2223 composites. Moreover, the elastic modulus (E), yield strength (Y), fracture toughness (K), brittleness index (B), and elastic stiffness coefficient (C11) were estimated as a function of the inclusion of nano-(Ba0.5Sr0.5Fe12O19)x. Furthermore, the indentation creep test (time-dependent Vickers microhardness) revealed that the dislocation creep mechanism exists in composite samples with low concentrations (x < 0.05 wt%), whereas the dislocation climbs creep mechanism was observed for x ≥ 0.05 wt%. [ABSTRACT FROM AUTHOR]

To compare between the effect of partial substitution of lead ions (Pb4+ and Pb2+) at thallium (Tl) site in Tl0.8-xHg0.2PbxBa2Ca2Cu3O9−δ superconductor; two different compounds, lead (II) oxide (PbO) and lead (IV) oxide (PbO2), were used for the synthesis of the superconducting samples. Samples with nominal compositions Tl0.8-xHg0.2PbxBa2Ca2Cu3O9−δ, with x = 0.00, 0.05, 0.10, 0.15, and 0.20, were synthesized via solid state reaction technique. The x-ray diffraction (XRD) results showed that the partial substitution of both lead ions has not affected the tetragonal structure. Moreover, the volume fraction was increased from 75.95% to 90.38% and 89.41% as x increased up to 0.20 for PbO and PbO2 substitutions, respectively. The scanning electron microscopy (SEM) images demonstrated better grain connectivity and rectangular-shaped plates, supporting the phase formation of (Tl,Hg)-1223. The energy-dispersive x-ray (EDX) analysis revealed good agreement between the nominal and real compositions. Moreover, the elemental composition and oxidation states were proved by x-ray photoelectron spectroscopy (XPS). Both the superconducting transition temperature (Tc) and critical current (Jc) showed enhancement at x = 0.5 and 0.1 for PbO and PbO2 substituted samples, respectively. Vickers microhardness (Hv) measurements were used to examine the mechanical properties of the composites under a range of applied loads (0.49–9.8 N). All the prepared composites revealed the normal indentation size effect. The proportional sample resistance model proved to be the best model for interpreting the experimental data for the prepared samples. [ABSTRACT FROM AUTHOR]

This investigation studies the effect of Mn and Sm co-dopants on the properties of CdO nanostructures. With the aid of co-precipitation technique, Cd1–2xMnxSmxO (x = 0.00, 0.005, 0.01, 0.02, 0.03, and 0.04) nanostructures, denoted by CdO, co-0.5, co-1, co-2, co-3 and co-4, respectively were synthesized. The crystallinity and phase formation of the prepared samples were confirmed by X-ray powder diffraction. The doped samples exhibited larger lattice parameters and strain as compared to the pure sample. Transmission electron micrographs revealed the formation of nanowires for pure and low co-doped concentrations and nanowires with nanoclusters for higher co-doped concentrations. The Raman spectra disclosed the major phonon modes of CdO without any indicator from the co-dopants, proving that they were well integrated into the CdO lattice. The UV–Vis spectra revealed the tunable energy gap with the co-dopants' concentration. The photoluminescence spectroscopy indicated the abundance of Cd interstitials and O/Cd vacancies. The DC conductivity indicated the metallic behavior of the prepared samples, triggered by Cd2+ vacancies, and the semiconducting behavior at high temperatures for co-1 and co-2. CdO and co-0.5 showed a weak ferromagnetic behavior combined with diamagnetic behavior; however, superparamagnetic along with an antiferromagnetic behavior was detected for higher doping concentrations. The origin of ferromagnetism may be related to O/Cd vacancies. Remarkably, all the samples prevented the growth of bacteria and formed well-defined zones around the samples with a stronger antibacterial activity on gram-negative (Escherichia coli, Citrobacter Braakii, and Klebsiella pneumoniae) than that on gram-positive bacteria (Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus intermedius). [ABSTRACT FROM AUTHOR]

The impact of adding the orthoferrite NdFeO3, at the nanoscale, on the (Cu0.5Tl0.5)Ba2Ca2Cu3O10–δ phase formation, microstructure, electrical and mechanical performance was studied. The nano-(NdFeO3)x/(CuTl)-1223 composites, with x = 0.00, 0.25, 0.50, 0.75, 1.00, and 2.00 wt.%, were prepared using the solid-state reaction technique. The X-ray diffraction (XRD) confirmed that supplementing the host (CuTl)-1223 phase with nano-NdFeO3 did not alter the unit cell parameters (a and c) and preserved the tetragonal structure. SEM micrographs suggested that the inclusion of nano-NdFeO3 reduced the number of voids and boosted the inter-grain connections. The energy-dispersive X-ray (EDX) spectra revealed the elemental compositions of the various superconductor composites. The superconducting transition temperature (Tc) and the critical current density (Jc) increased with the inclusion of nano-NdFeO3 up to x = 0.50 wt.%. X-ray photoelectron spectroscopy (XPS) spectra analysis revealed the elemental composition and oxidation state of all elements. The Vickers microhardness (Hv) measurements were analyzed and compared with five different theoretical models. According to Hv measurements, the modified proportional sample resistance (MPSR) model provided the best theoretical analysis of Hv within the plateau limit regions. Moreover, various mechanical parameters were estimated as a function of the inclusion of nano-NdFeO3. The indentation creep test showed that the composite samples with high nanoparticle concentration (x > 0.50 wt.%) have dislocation creep mechanism, while those with x ≤ 0.50 wt.% followed a dislocation climbs creep mechanism. A comparison between NdFeO3 nanoparticles and other magnetic ferrites and nano-magnetic oxides was reported. [ABSTRACT FROM AUTHOR]

The magnetoresistance behavior of (CuF2)x-substituted (Cu0.5−x, Tl0.5)Ba2Ca2Cu3Oy superconducting samples with x = 0.1, 0.2, 0.3, and 0.4 was investigated by varying the flux pinning mechanism. A pronounced broadening of resistive transitions, ΔT, was observed by applying external magnetic fields ranging from 0.29 to 4.40 kOe. The thermally activated flux creep, TAFC, and Ambegaokar–Halperin, AH, models have been studied to explain the broadening of the resistive transition and magnetoresistance. The results revealed that the flux pinning energy, U(H), was reduced as the magnetic field increased while it was raised with increasing (CuF2)x substituted up to an optimum concentration of x = 0.2. Moreover, the critical current density, Jc, and the upper irreversibility field, Hirr, were enhanced with (CuF2)x—substituted in the (Cu0.5−x, Tl0.5)Ba2Ca2Cu3Oy phase, showing a strong flux pinning for x = 0.2 at different magnetic fields. [ABSTRACT FROM AUTHOR]

In the present work, the magnetoresistance behavior of (TlF)x-substituted (Cu0.5,Tl0.5)Ba2Ca2Cu3O10−δ superconducting samples, with x = 0.0, 0.1, 0.2, 0.3 and 0.4, was investigated. According to the thermally activated flux creep (TAFC) model, the flux pinning energies U(H, T) were calculated from the resistivity temperature (ρ–T) curves at applied DC magnetic fields ranging from 0.29 to 4.44 kOe. The results indicated that flux pinning energy was increased with increasing the F-substituting up to x = 0.1 and then decreased with increasing the applied field up to 4.44 kOe. Moreover, significant resistive broadening (ΔT) was observed with increasing the values of the applied magnetic fields. Furthermore, the (TlF)x substitution, boosting the transport critical current density Jc(0) and irreversibility magnetic field Hirr(0) up to x = 0.1 and then decreasing for x > 0.1 at various applied magnetic fields, demonstrates strong flux pinning for x = 0.1. [ABSTRACT FROM AUTHOR]

In this study, the influence of adding Yttrium iron garnet (Y3Fe5O12) nanoparticles (NPs) on the microstructure and fluctuation-induced conductivity (FIC) of Cu0.5Tl0.5Ba2Ca2Cu3O10-δ (CuTl-1223) superconductor was studied. Y3Fe5O12 NPs were produced by the co-precipitation technique. By solid state route, (Y3Fe5O12)x/Cu0.5Tl0.5Ba2Ca2Cu3O10-δ composites, with x = 0.00, 0.02, 0.04, 0.06, 0.08, and 0.10 wt. % were prepared. The tetragonal unit cell parameters of (Y3Fe5O12)x/Cu0.5Tl0.5Ba2Ca2Cu3O10-δ composites were found to be invariable with Y3Fe5O12 content. The volume fraction of the host phase was increased with Y3Fe5O12 addition till x = 0.04 wt. %. The different vibrational modes of the samples were identified through Fourier transform infrared spectroscopy (FTIR). The transition from normal to the superconducting state, for the prepared composites, was done through d.c resistivity measurements from room temperature down to zero critical temperature (T0). The Aslamazov–Larkin (AL) model was used to examine fluctuation regions in resistivity-temperature curves. At high temperatures, short wave fluctuation was observed. A cross-over between short wave fluctuation and the mean-field region was spotted at lower temperatures. The mean field region for the examined composites was composed of two-dimensional fluctuations along with one-dimensional fluctuation. The coherence length along the c-axis ζc(0), interlayer coupling (J), and anisotropy parameter (γ) were estimated from the Lawrence–Doniach (LD) model as a function of Y3Fe5O12 content. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Structural, cation distribution, mechanical, and optical properties of rare-earth doped cadmium zinc ferrites" published in Applied Physics A: Materials Science & Processing. The correction notice addresses two errors in the original article. Firstly, the affiliation details for Khulud Habanjar were incorrectly given and should have been only affiliation 1. Secondly, Figs 4 and 5 were wrongly numbered and should have been switched. The original article has been corrected. The publisher, Springer Nature, remains neutral regarding jurisdictional claims and institutional affiliations. The authors of the article are Hani Korek, Khulud Habanjar, and R. Awad. [Extracted from the article]

Pure and lanthanum-doped zinc oxide nanoparticles (Zn1-xLaxO), with atomic percentages ( x = 0, 1, 3, 5 and 7 at%) were prepared by chemical co-precipitation method. The synthesized samples have been characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy, photoluminescence spectroscopy (PL) and M-H loop using vibrating sample magnetometer (VSM). XRD analysis reveals the wurtzite hexagonal crystal structure of ZnO structure with the detection of lanthanum oxide secondary phase (La2O3) for x ≥ 3 at%. The increase of the lanthanum content affects the particles size, energy bandgap and lattice parameters. The presence of functional groups and the chemical bonding is confirmed by FTIR spectra that shows the formation of additional peaks due to ZnO ions dopant. The direct energy bandgap was calculated, showing a noticeable change as the concentration of the lanthanum content increases. The photoluminescence spectra show 8 emission peaks due to different defects. The M-H curves exhibited a combination of both diamagnetic and ferromagnetic contributions. The antibacterial activity of the synthesized samples was studied against three gram-negative (Escherichia coli, Klebsiella pneumoniae, and Citrobacter braakii) and three gram-positive (Staphylococcus aureus, Staphylococcus haemolyticus, and Streptococcus intermedius) bacterial strains using agar well diffusion method. These nanoparticles exhibited various degrees of antibacterial activity against the investigated bacteria. [ABSTRACT FROM AUTHOR]

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This work uses the co-precipitation method for the synthesis of Zn1-xRuxO nanoparticles, with (0 ≤ x ≤ 0.04). Structurally, Rietveld refinement of X-ray powder diffraction data revealed the hexagonal wurtzite crystal structure, for all samples, with minor traces of RuO2 for x > 0.01. Fourier transform infrared spectroscopy confirmed the formation of ZnO wurtzite structure with a broad peak at 441 cm−1 and a shoulder at 565 cm−1. Optical band gap (Eg) was investigated through UV–visible spectroscopic analysis. Eg showed an enhancement with the increase of Ru content verifying the decrease in the crystalline size from XRD results. Magnetic properties were investigated by the vibrating sample magnetometer. Ferromagnetism in ZnO was justified by the formation of bound magnetic polarons (BMPs). It shows an enhancement with Ru doping, verified by the increase of both Mr and Ms, attributed to the stabilization of Zn vacancy as well as magnetic defects. [ABSTRACT FROM AUTHOR]

The current investigation reports the influence of the addition of CdFeO nanoparticles on the structural and superconducting properties of the (Bi,Pb)-2212 phase. The formation of an orthorhombic phase of Bi-2212 superconductor is confirmed by the X-ray powder diffraction measurements. The scanning electron microscope measurements show an improvement in the grain connectivity and a decline of voids due to the CdFeO nanoparticles addition. The Fourier transform infra-red spectroscopy is used to associate the absorption bands to equivalent functional groups. The DC-electrical resistivity and the I-V characteristic measurements show an enhancement of the superconducting transition temperature (Tc) and the critical current density (Jc) up to 0.02 wt% addition of CdFeO, respectively. The elemental composition and oxidation states are determined using X-ray photoelectron emission spectroscopy. The results suggest a correlation between the electric behavior and the cationic equilibrium reactions among Pb2+ ions in Bi3+ or Cu2+ sites. [ABSTRACT FROM AUTHOR]

The effect of CdMnO addition on the physical properties of Bi-2212 superconductors was investigated. The conventional solid-state reaction technique was employed for the synthesis of (Cd0.95Mn0.05O)x Bi1.6 Pb0.4 Sr1.9 Ca1.1 Cu2.1 O8+δ samples with 0.00 ≤ x ≤ 0.10 wt.%. The X-ray diffraction confirms the formation of the orthorhombic phase of Bi-2212 superconductors. The lattice parameter a shows an increase with x, conversely the lattice parameters b and c show a decrease. The scanning electron microscope (SEM) images have shown an enhancement in the grain connectivity and a reduction of voids due to the CdMnO addition. The Fourier transform infrared (FTIR) spectroscopy analysis shows a remarkable shift in the wave number positions due to the addition of CdMnO nanoparticles. The superconducting transition temperature (Tc) and the critical current density (Jc) show an enhancement with CdMnO addition up to x = 0.05 wt.%. The elemental composition and oxidation state of all elements were determined from the X-ray photoelectron emission (XPS) analysis. The work suggests a correlation between the variations of the superconducting properties and the dynamics of the cationic equilibrium reactions among Pb2+ ions in Bi3+ or Cu2+ sites. These equilibrium reactions are induced by the variations in the oxygen content produced by the addition of CdMnO nanoparticles. [ABSTRACT FROM AUTHOR]

The preparation and characterization of ZnRuxFe2−xO4 (0.00 ≤ x ≤ 0.015) nanoparticles are reported in the current investigation. The successful synthesis of monocrystalline ZnRuxFe2−xO4, by wet coprecipitation method, with high purity and crystallinity in the nanoscale was confirmed via x-ray powder diffraction and transmission electron microscopy. The crystallite size of ZnRuxFe2−xO4 nanoparticles has decreased due to microstrain induced by Ru3+ substitution. EDX investigations have assured the elemental compositions of all prepared samples. The optical studies, conducted via UV–vis spectroscopy analysis, have shown an increase in both direct and indirect bandgap energies, in relation to the quantum size confinement effect. Additionally, PL studies have revealed UV and deep level emissions for all samples. The analysis of the PL spectra suggested an increase in the photocatalytic activity of Ru3+ substituted ZnFe2O4 nanoparticles. Finally, VSM studies have shown unsaturated M-H loops for all samples with a soft ferromagnetic signature at lower fields. The analysis of the magnetic parameters suggests the use of ZnRuxFe2−xO4 as magnetically recyclable photocatalysts. [ABSTRACT FROM AUTHOR]

The characterization of Nanosized Ni0.5Zn0.5RuxFe2−xO4 (0.00 ≤ x ≤ 0.015), prepared by the wet chemical coprecipitation method, is reported in the current investigation. X-ray powder diffraction (XRD) analysis has confirmed the formation of a single phased spinel cubic structure. While transmission electron microscopy (TEM) studies have shown an increase in the particle size for high content of Ru3+ doping. The elemental composition of all samples was investigated using energy dispersive x-ray (EDX) measurements. The results showed a reciprocal relation between the Fe3+ and Ru3+ contents, suggesting the successful substitution of Ru3+in Fe3+ sites. UV–Vis spectroscopy studies, via Urbach energy analysis, proposed a perturbation in the band structure of Ni0.5Zn0.5Fe2O4 induced by Ru3+ substitution, affecting both the direct and indirect bandgap energies. Excitation wavelength-dependent photoluminescence (PL) studies, presented for the first time, have shown a strong dependence of the emission spectra on both the excitation wavelength and Ru3+ doping. The PL analysis suggests the utilization of Ni0.5Zn0.5RuxFe2−xO4 as a candidate for photocatalytic applications. Furthermore, VSM studies, have shown a transition from superparamagnetic to soft ferromagnetic for Ru3+ doped samples. The saturation magnetization, coercivity, and effective anisotropy were enhanced as a result of Ru3+ doping. Finally, photocatalysis experiments have shown an enhancement of the degradation rate of nitrobenzene for the sample with x = 0.0125 with the ability of magnetic recycling, in agreement with the PL and VSM studies. [ABSTRACT FROM AUTHOR]

Recent advancements in the field of immune-oncology have led to a significant increase in life expectancy of patients with diverse forms of cancer, such as hematologic malignancies, melanoma and lung cancer. Unfortunately, these encouraging results are not observed in the majority of patients, who remain unresponsive and/or encounter adverse events. Currently, researchers are collecting more insight into the cellular and molecular mechanisms that underlie these variable responses. As an example, the human lymphocyte activation gene-3 (huLAG-3), an inhibitory immune checkpoint receptor, is increasingly studied as a therapeutic target in immune-oncology. Noninvasive molecular imaging of the immune checkpoint programmed death protein-1 (PD-1) or its ligand PD-L1 has shown its value as a strategy to guide and monitor PD-1/PD-L1-targeted immune checkpoint therapy. Yet, radiotracers that allow dynamic, whole body imaging of huLAG-3 expression are not yet described. We here developed single-domain antibodies (sdAbs) that bind huLAG-3 and showed that these sdAbs can image huLAG-3 in tumors, therefore representing promising tools for further development into clinically applicable radiotracers. [ABSTRACT FROM AUTHOR]

Pure and Gd-doped NiO nanoparticles capped by polyvinylpyrrolidone (PVP) were synthesized via the co-precipitation method, with different concentrations (x = 0.000, 0.005 and 0.010). Extensive experimental assessments were conducted to study the structural, optical and magnetic properties of the prepared nanoparticles. The X-ray diffraction patterns depicted the formation of pure NiO phase without impurities, assuring the adequate incorporation of Gd dopants into the lattice. The transmission electron micrographs showed the pseudospherical morphology of the pure and Gd-doped samples, with mean sizes, ranging between 28.09 and 22.84 nm. The vibrational spectroscopies confirmed the purity of the synthesized samples and gave insight into their structural properties. Moreover, the excitation dependence of the photoluminescence emission spectra was noticed due to the particles' size distribution. Some point defects, as the nickel and oxygen vacancies, were tuned upon the introduction of Gd dopants, leading to enhancements in the optical and magnetic properties. The optimum concentration of Gd dopants was x = 0.005 in Ni1-xGdxO nanoparticles since it attained the widened bandgap energy of 3.46 eV and highest saturation magnetization of 0.23 emu/g at an applied field of 20 kG. All the samples demonstrated weak ferromagnetic nature, which was deduced from the M-H loops after subtracting the linear magnetization of the antiferromagnetic contribution. The Belov–Arrot plot showed a second-order magnetic transition from antiferromagnetic to ferromagnetic nature. The improvements in PVP-capped Gd-doped NiO nanoparticles are fruitful for light-emitting devices and spintronic applications. [ABSTRACT FROM AUTHOR]

A series of (Cu0.5−xTl0.5−y)-1223 superconductor samples, doped with varying amounts of (CuF2)x and (TlF)y compounds with x = y = 0.0, 0.1, 0.2, 0.3 and 0.4, were synthesized via a single-step solid-state reaction. X-ray diffraction (XRD) revealed that all the samples have a tetragonal symmetry of (Cu0.5Tl0.5)-1223 phase. Additionally, with increasing fluorine content up to x = 0.2 CuF2 and y = 0.1 TlF, the phase fraction and the superconducting transition Tc were enhanced. The scanning electron microscopy (SEM) images exhibited mainly plate-like rectangular shape grains confirming the formation of (Cu0.5Tl0.5)-1223 phase. The Fourier transform infrared (FTIR) spectra of CuF2- and TlF-substituted (Cu0.5−xTl0.5−y)-1223 show a slight softening and hardening in few peaks related to the apical oxygen atoms and CuO2 planar modes. The stoichiometry of elemental composition for all prepared samples has been confirmed using ion beam analysis (IBA) methods. The excess conductivity Δσ above Tc was analyzed through the Aslamasov–Larkin (AL) approach. Using the Ginzburg–Landau (GL) number (NG) and equations, the coherence length, the effective layer thickness, the lower critical field Bc1(0), the upper critical field Bc2(0) and the critical current density Jc(0) were estimated. It was found that the addition of an optimum concentration of CuF2 and TlF, controlled the microstructure, the grains coupling and hence enhanced the physical properties of (Cu0.5Tl0.5)-1223 phase. [ABSTRACT FROM AUTHOR]

Pure CdO nanoparticles were prepared by co-precipitation method at different calcination temperatures (550, 600, 650, and 700 °C) and different pH (10, 11, 12, and 13). This investigation is intended to study the effect of the different preparation conditions on the physical properties of the obtained CdO nanoparticles. The crystal structure, morphology, elemental content, and functional groups of the CdO nanoparticles were investigated using X-ray powder diffraction (XRD), Transmission electron microscopy (TEM,) Energy-dispersive X-ray (EDX), and Fourier transform Infrared (FTIR), respectively. The crystallinity and the particle size of CdO nanoparticles were both enhanced with the increase in temperature. As for pH variation, the samples prepared at pH = 10 and 11 have shown a multiphase XRD spectrum, attributed to the incomplete reduction in CdO. The EDX and FTIR results confirmed the stoichiometry of the samples and the existence of Cd–O vibrational bonds. The optical properties were studied using room temperature UV–Vis and PL spectroscopies. The energy bandgap showed a decrease with temperature and was found particle size-dependent. The PL emission spectra showed deep level violet and blue emissions with maximum intensities at pH = 12 and T = 650 °C. The magnetic properties were examined using M-H measurements. The curves showed a combination of diamagnetic and ferromagnetic contributions for all samples. The Differentiation-Deconvolution-Selective Integration (DDSI) method was utilized to isolate the ferromagnetic contribution and determine the magnetic parameters. The broad particle size distribution of the prepared nanoparticles is considered to be the key factor in understanding the magnetic behavior of the samples. Accordingly, this work reveals that the structural, optical, and magnetic properties of CdO nanoparticles can be tuned by applying different preparation conditions allowing for numerous applications. [ABSTRACT FROM AUTHOR]

(BaSnO3)x/Cu0.5Tl0.5Ba2Ca2Cu3O10-δ superconducting composites (0.00 ≤ x ≤ 1.50 wt.%) were prepared by the solid-state reaction technique. The crystalline structure and superconducting transition temperature were investigated by X-ray powder diffraction (XRD) and dc-electrical resistivity measurements, respectively. X-Band electron spin resonance (ESR) measurements were carried out at different temperatures 103 ≤ T ≤ 298 K. ESR spectra are dominated by a single asymmetric line corresponding to Cu2+ ions at the rhombic site. The temperature dependence of the g factors allowed the determination of the pseudo-gap onset temperature T*. The results of T* are compatible with those obtained from resistivity and thermoelectric power measurements. The contribution of delocalized electrons from Cu2+ ions in the disordered part of the impurity phases BaCuO2 and Ba2CuO3 is significant for the high addition of nanoparticles. Moreover, the number of spins N participating in ESR and the activation energy Ea were enhanced with the addition of BaSnO3. [ABSTRACT FROM AUTHOR]

In this work, spinel zinc ferrite (ZnFe2O4), manganese oxide (Mn2O3) nanoparticles (NPs) as well as a series of ZnFe2O4/Mn2O3 nanocomposites (NCs) with varying Mn2O3 ratio from 10 to 50 wt. % were synthesized by co-precipitation route. The structural, optical, electrical, and magnetic properties of ZnFe2O4/Mn2O3 NCs were examined by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), ultraviolet–visible (UV–Vis) spectroscopy, photoluminescence (PL) emission, DC electrical conductivity, and vibrating sample magnetometer (VSM). The XRD analysis demonstrated the existence of Mn2O3 and ZnFe2O4 phases, in addition to the formation of spinel ZnMn2O4 and α-Fe2O3 as secondary phases. The chemical interactions between the Mn2O3 and ZnFe2O4 have been confirmed by the shift in the position of the metal–oxygen (M–O) stretching modes in the FTIR spectra. The TEM images revealed the presence of cubic and spherically shaped nanoparticles in the ZnFe2O4/Mn2O3 NCs with an average size in the range of 15.52 to 19.22 nm. The nanocomposites showed strong absorption in the UV region with a calculated bandgap ranging between 3.22 and 3.26 eV. However, the nanocomposite with 10 wt. % Mn2O3 exhibited the highest photocatalytic activity under UV-irradiation as confirmed by PL spectroscopy. Moreover, the nanocomposite structure exhibited a significantly enhanced DC conductivity compared to ZnFe2O4 and attained a maximum value at 10 wt. % Mn2O3. The room temperature M-H curves of ZnFe2O4/Mn2O3 NCs displayed weak ferromagnetic behavior. The magnetization increases with increasing Mn2O3 content up to 10 wt. % and then decreases with further increase in the wt.%. [ABSTRACT FROM AUTHOR]

The current study was carried out on six Iraqi breed rams, aged between 2 to 4 years, during the period from Nov. 2018 to the Mar. 2019. Semen samples were collected from each ram with electro ejaculator at the morning, one ejaculate per week over a time of 16 weeks. Pooled semen for all rams were used to evaluate the characteristics of semen to avoid individual variation between the animals. The volume and the color offresh semen was recorded directly, then semen was evaluated for mass and individual motility, live/dead percentage and sperm abnormalities. Semen samples were diluted 1:10 with a Tris-based extender, and divided into seven parts (each part 2ml), 0.1µml, 1.0µml & 3.0µml concentration of melatonin were added to the T1, T2 and T3 respectively, L-arginine were added to the T4, T5 and T6 in 0.001µmol, 0.1µmol and 1.0µml concentration respectively while T7 serve as a control without any addition. All treatments cooled at 4°c. Then semen parameters evaluated. It was concluded from this study that addition of 0.1 µmol melatonin significantly protected ram sperm cell from cold storage that induced negative effects on sperm function. However the addition of L-arginine have no beneficial effect on cooled ram semen. [ABSTRACT FROM AUTHOR]

The effect of Arsenic substitution on the properties of Bi-2212 superconductors was studied. Solid-state reaction technique was used for the synthesis of Bi2−xAsxSr2Ca1.1Cu2.1O8 samples, x = 0, 0.1, 0.2 and 0.4. The X-ray diffraction confirmed the formation of the tetragonal phase of Bi-2212 superconductors. The decrement in the c parameter confirmed that As insertions were introduced into the Bi sites of the system. The grain morphology of the surface was analysed by scanning electron microscopy, where the amount of arsenic increases with As substitution. The superconducting transition temperature (Tc) was determined from the DC-electrical resistivity by the standard four-probe technique. Tc was enhanced up to x = 0.1 above which it was suppressed. For magnetism, half magnetic-hysteresis loops were obtained by SQUID magnetometer at different temperatures (5 and 30 K). The hysteresis loops sizes increased with increasing As-concentrations. The critical current density (Jc) and the flux pinning mechanisms were investigated via different models. [ABSTRACT FROM AUTHOR]

(Mn2O3)x SmBa2Cu3O7-δ composite samples (0.00 ≤ x ≤ 0.08 wt.%) were prepared using solid state reaction technique, and investigated using resistivity measurements and the Vickers microhardness. The characterisation of the prepared samples was accomplished using X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), and Brunauer-Emmett-Teller (BET). The Mn2O3 nanoparticles do not influence the orthorhombic structure of SmBa2Cu3O7- δ and stay as adhering material producing a filling up of the voids and reducing the cracks. BET measurements show a decrease in the specific surface area as well as in the total pore volume for x = 0.02 wt.%, confirming the SEM results. The superconducting transition temperature Tc of the prepared samples was investigated using electrical resistivity measurements. Results showed that Tc increases from 91.68 K to 94.43 K as x increases from 0.00 to 0.02 wt.%, then it decreases as nano-Mn2O3 wt.% concentration increases. The mechanical properties of (Mn2O3)xSmBa2Cu3O7-δ samples were measured using Vickers microhardness in order to investigate the effect of Mn2O3 nanoparticles on Vickers microhardness number Hv. The Vickers microhardness data were analysed using Meyer's law, Hays and Kendall (HK), and Modified Proportional Specimen Resistance (MPSR) models. The analysis showed that the HK is the best model to describe the load dependence of Hv for all samples. [ABSTRACT FROM AUTHOR]

Magnetic nanoparticles MnFe2-xMoxO4 (x = 0.00, 0.04, 0.08 and 0.10) have been prepared by wet coprecipitation method at calcination temperature 673 K. X-ray powder diffraction (XRD) was used to study the structural properties of the prepared samples, whereas the vibrating sample magnetometer (VSM) and Mössbauer spectrometry measurements (at T = 300 K and T = 77 K) were used to investigate the magnetic properties. The single-phase cubic spinel structure of the ferrites samples was confirmed by the XRD patterns, and a nonlinear variation in the crystalline size was revealed. VSM hysteresis loops confirmed the ferromagnetic behavior in all the samples with an increase in saturation magnetization with the molybdenum doping. Mössbauer spectra at 300 K showed a mixture of the magnetic sextet and central quadrupole doublet with enhancement in the magnetic sextet in the Mo-doped samples. Moreover, Mössbauer spectra at 77 K revealed the disappearance of the quadrupole doublet in all samples, indicating the enhancement of magnetic properties of manganese ferrites nanoparticles due to Mo-doping. [ABSTRACT FROM AUTHOR]

In the search for highly responsive dielectric materials, superconducting samples of type (Bi,Pb)-2223 were prepared using the standard solid-state reaction technique, with the addition of three different concentrations of ferrato and mangano-undecatungstosilicate (0.04, 0.12, and 0.20 wt%). The dielectric studies were performed by measuring the parallel capacitance C p as well as the dielectric loss factor using LCR HiTESTER. The studies were performed at temperature and frequency ranges starting from room temperature down to 98 K and from 50 kHz up to 5 MHz, respectively. The dielectric behavior was investigated by calculating both dielectric constants ( ε ′ and ε ″ ), loss tangent (Tanδ) and ac conductivity (σac) as a function of frequency, temperature and addition concentrations of the {FeSiW11} and {MnSiW11} polyoxometalates. The results revealed that the dielectric parameters decrease with increasing frequency at each temperature for all the {FeSiW11}x(Bi,Pb)-2223 and {MnSiW11}x(Bi,Pb)-2223 prepared samples. Moreover, ε ′ and σac showed a decreasing trend with an increase in temperature in contrast to the increasing trend shown by ε ″ and Tanδ. Additionally, ε ″ has decreased upon increasing temperature at low frequencies. Accordingly, low {MnSiW11} addition at 0.12 wt% exhibited the highest dielectric constant 1.99 × 10 7 and ac conductivity 61.449 (Ω.m)−1 with minimum dissipation (1.078). Furthermore, the ac conductivity was studied according to the power law, and the frequency exponent was found greater than one 1.654 ≤ S ≤ 1.759 for all the prepared samples. [ABSTRACT FROM AUTHOR]

(xCo)-BaFe12O19 nanoparticles, with 0 ≤ x ≤ 0.1 wt%, have been prepared using a chemical co-precipitation method and different calcination temperatures (850 °C, 900 °C and 950 °C). The samples were subjected to structural, optical and magnetic studies. X-ray powder diffraction showed the hexagonal crystal structure of (xCo)-BaFe12O19, and the more convenient temperature for the formation of this phase was 950 °C. Transmission electron microscope was used for investigating the morphology as well as the average particle size of the samples. It was found that the average size of all samples ranges between 65 and 90 nm. The energy band gap Eg was determined using UV–Vis spectroscopy. It was noticed that the values of Eg decreased with the addition of cobalt and the increase in the calcination temperature. The M–H curve obtained from vibrating sample magnetometer has been used to study the magnetic behavior. The anisotropy field (Ha), the saturation magnetization (σs), the effective crystalline anisotropy constant (Keff), the remanent magnetization (σr) and squareness ratio (S) for each sample were calculated. The maximum value of coercivity (5087Oe) was found for x = 0 wt% at T = 950 °C which is suitable for magnetic applications, such as the recording equipment and permanent magnets. [ABSTRACT FROM AUTHOR]

Pure and a series of rare earth element (RE) (Er, Sm, Gd, Pr and Y)-doped NiO nanoparticles (NPs) were fabricated by co-precipitation method in the presence of polyvinyl alcohol as a capping agent. X-ray diffraction (XRD) and transmission electron microscope (TEM) techniques were used to investigate the crystal structure and morphology of the prepared samples, respectively. The XRD patterns indicated that all the samples exhibited a single phase of face-centered cubic crystalline structure. TEM images displayed a spherical morphology of weakly agglomerated NPs. Furthermore, the chemical compositions were identified by proton-induced X-ray emission and Rutherford backscattering analysis. The metal oxide (Ni–O) functional group was confirmed by Fourier transform infrared spectroscopy with its observed band varying from 419.3 to 433.3 cm−1, depending on the RE doping element. The optical properties of the RE-doped NiO NPs were studied using UV–Vis absorption and photoluminescence (PL) spectroscopy. A small blueshift was obtained in the optical spectra of the RE-doped samples as compared to the undoped samples, implying an increase in the optical band gap. The study of the room temperature magnetic properties was done using the vibrating sample magnetometer, which revealed the coexistence of antiferromagnetic and weak ferromagnetic ordering in pure and RE3+-doped NiO NPs. The magnetization increased depending on the magnetic moments of RE dopant ions. Also, the origin of the anomalous ferromagnetism in the prepared samples may be mainly related to Ni vacancy defects, which were evinced from the results of PL. [ABSTRACT FROM AUTHOR]

Tricobalt tetroxide (Co3O4) nanoparticles were synthesized by co-precipitation method. The structure, morphology, purity, real compositions, and functional groups of the prepared nanoparticles were determined by X-ray diffraction (XRD), transmission electron microscope (TEM), energy-dispersive X-ray (EDX) analysis, and Fourier transform infrared (FTIR) spectroscopy, respectively. The results confirm the formation of pure spinel structure of the Co3O4 nanoparticles with space group Fd3m and average spherical particle size of 58 nm. The optical properties were explored by ultraviolet–visible spectroscopy (UV–vis) and photoluminescence spectroscopy (PL). Two absorption peaks were aroused in ultraviolet and visible ranges accompanied by two band gap energies and an Urbach energy. Moreover, two emission peaks in agreement with the calculated band gap energies were observed in the PL spectrum. A weak ferromagnetic behavior was investigated by magnetic hysteresis (M-H) loop at room temperature. The electrical conductivity was measured in the temperature range 313–573 K. A normal semiconductor behavior was detected. The dielectric properties were studied under the variation of temperature and frequency. Then, the dielectric constant, dielectric loss, ac conductivity, relaxation process, and Nyquist plots were discussed. [ABSTRACT FROM AUTHOR]