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The effect of randomly distributed Ca dopants within the BaTiO3 lattice was investigated using first principle calculations. We examined electronic properties to understand how different orbitals contribute to the conduction and valence bands in doped materials. Our findings indicate that the valence band is primarily composed of Ti-3d and O-2p orbital states, while the conduction band is influenced by the collective contributions of Ba-4d, Ti-3d, and Ca-3d orbital states. Additionally, our results demonstrate a reduction in the bandgap due to Ca doping, with the extent of variation depending on the substituted sites of the Ca atoms. Furthermore, we investigated modifications in optical properties such as absorption, conductivity, dielectric function, refractive index, extinction coefficient, loss function, and reflectivity in the energy range from 0 to 40 eV. The findings reveal the stability of these characteristics in the infrared and visible light regions, and they also depend on the site substitution of Ca cations within the BaTiO3 lattice. We expected that our findings would deepen the understanding of the mechanism and site effect of Ca dopant on the properties of BaTiO3 materials, thereby contributing to the development of lead-free ferroelectric materials with enhanced properties for multifunctional applications. [ABSTRACT FROM AUTHOR]

The strongly enhanced room temperature ferromagnetism in Bi0.5Na0.5TiO3 materials was obtained via modification of YMnO3 as solid solutions. The weak ferromagnetism in pure Bi0.5Na0.5TiO3 was changed to ferromagnetism and antiferromagnetic-like with increasing the concentration of YMnO3 addition. The maxima magnetic moment was estimated at around 28.4 memu/g for 9 mol.% YMnO3-modified Bi0.5Na0.5TiO3 as a solid solution. The reduction of the optical bandgap energy from 3.18 eV to 2.01 eV was obtained via increasing YMnO3 addition into host Bi0.5Na0.5TiO3 crystal as solid solutions with amounts up to 9 mol.%. We suggested that the observation in the reduction of optical bandgap energy and great enhancement of the magnetic moment in YMnO3-modified Bi0.5Na0.5TiO3 compounds were strongly related to the random distribution of Y and Mn cations into the host lattice of Bi0.5Na0.5TiO3 crystals. We expected that our work will provide a simple way to integrate room temperature ferromagnetism into currently developed green ferroelectric materials. [ABSTRACT FROM AUTHOR]

The complex surface defects induced magnetic properties of lead‐free ferroelectric Bi0.5Na0.5TiO3 (110) materials system are investigated by using the density‐functional theory. Various types of surface defects were considered for calculation, including antisite, vacancies and interstitial defects. The calculated results indicated that a perfect Bi0.5Na0.5TiO3 (110) surface produced zero magnetic moments. The conduction band was mostly contributed from Bi‐6p and Ti‐3d levels, where the valence band was built from O‐2p. The antisite defects where Na replaced for Bi‐site induced nonzero magnetic moments because of unsymmetrical spin O‐2p up and O‐2p down. While, the observation in nonzero magnetic moment of antisite defects Bi substitute for Na‐site were originated from Ti‐3d and Na‐2s. The Na and Bi vacancies on the surface were tuned to the ferromagnetic because of the unsymmetrical contribution of O‐2p, while the Ti and O vacancies were not. The Na and Bi surface interstitials induced the magnetic moments because of the contribution of the difference between Ti‐3d and Bi‐6p, respectively, while the Ti and O surface interstitials not induced the magnetic moments. We expected that our results could help to control chemical defects in new green multiferroic materials for smart electronic devices. [ABSTRACT FROM AUTHOR]

The Ni 1 − x CoxTiO3 (0 ≤ x ≤ 1) solid solution powders were prepared by an aqueous sol–gel method. The structural, optical, magnetic and ferroelectric properties of NiTiO3 were investigated by X-ray diffraction, scanning electron microscope, UV–Vis absorption, vibration samples magnetometer and ferroelectric test system. The X-ray diffraction analysis revealed that prepared materials were in a single phase with rhombohedral structure with x up to 1. The increasing Co content resulted in decreasing of tolerance factor and increasing of the lattice constant. The crystalline size increased with an increase of Co content. The optical bandgap value of solid solution increased from 2.23 eV for NiTiO3 to 2.36 eV for CoTiO3. The magnetic hysteresis loop results indicate that all samples showed paramagnetic state at room temperature. A correlation between magnetization values and composition of the materials was observed with magnetization values which increased with increasing of CoTiO3 content in solid solution. Ferroelectric polarization analysis showed that the polarization of the Ni 1 − x CoxTiO3 solid solution depended on x value and reached the maximum with x = 0. 4. [ABSTRACT FROM AUTHOR]

Er½Na½TiO3–Bi½Na½TiO3 solid solutions were prepared by a sol–gel technique. The complex distortion of the rhombohedral structure of host Bi½Na½TiO3 compounds was obtained caused by the addition of the solid solution of Er½Na½TiO3 into the host Bi½Na½TiO3 matrix. The random incorporation of Er3+ cations into the host crystal of the Bi½Na½TiO3 material resulted in reducing its optical band gap from 3.04 to 2.79 eV by increasing the Er½Na½TiO3 amount. The strong green emission at 550 nm was obtained at room temperature and is related to the emission of Er3+ cations from 4S3/2 to 4I15/2 levels. The observation of strong photoemissions at room temperature of Er½Na½TiO3-Bi½Na½TiO3 binary system promises to create the next generation of smart electronic devices. [ABSTRACT FROM AUTHOR]

Experimental and theoretical studies on hydrogen in diluted magnetic semiconductors and related materials have been reviewed. A strong modification of magnetic order has been found by co-doping of hydrogen and magnetic ions in diluted magnetic semiconductors, which depended on the states of hydrogen acting in both crystalline and amorphous. In addition, the hydrogen was found to be strongly active with the magnetic ions resulting in modification of the electrical, magnetic, band structure properties, etc. We expect that our review could help to make a direction for the experimental and theoretical guide to develop advanced functional materials in silicon technology. [ABSTRACT FROM AUTHOR]

A new solid solution system of binary (1-x)Bi1/2Na1/2TiO3 + xNd1/2Na1/2TiO3 compound was well synthesized by a chemical method. The structural studies by X-ray diffraction and Raman scattering techniques provided strong evidence for the complex incorporation of Nd3+ cations into the host Bi1/2Na1/2TiO3 crystal during the formation of solid solutions. The random substitution of Nd3+ cations at both A- and B-sites of the host Bi1/2Na1/2TiO3 crystal resulted in reducing the optical bandgap from 3.05 to 2.94 eV. The strong photoemission intensity in the near-infrared region, around 883–915 nm, was obtained at room temperature, which was related to electron transitions from 4F3/2 to 4I9/2 levels of Nd3+ cations. The observation in near-infrared photoemission of the new binary Nd1/2Na1/2TiO3-modified Bi1/2Na1/2TiO3 materials exhibited a new method successfully applied for the integration of photoluminescence in lead-free ferroelectric materials for further smart electronic device applications. [ABSTRACT FROM AUTHOR]

The mixed spinel—ilmenite nanocomposites of (1 − x)NiTiO3–xCoFe2O4 (x = 0, 0.05, and 0.10) have been synthesized by sol–gel method. In a one-pot synthesis method, both the constituent phases of composites are formed during the same time of the synthesis process. X-ray powder diffraction gave evidence of the phase purity of the systems. CoFe2O4 phase modified the optical band gap of NiTiO3 materials, shifted the optical band-gap value NiTiO3 toward lower energy. Optical band-gap values decreased from 2.23 to 1.51 eV for pure NiTiO3 and 10 mol% CoFe2O4-modified NiTiO3 samples, respectively. NiTiO3–CoFe2O4 composites with 5 and 10 mol% CoFe2O4 fractions were found to enhance the ferroelectric and magnetic properties of NiTiO3 at room temperature. The remanent polarization (Pr) increased from 0.017 to 0.182 µC/cm2 and saturation polarization (Ps) increased from 0.056 to 0.219 µC/cm2 for NiTiO3 and 10 mol% CoFe2O4-modified NiTiO3 sample, respectively. The saturation magnetization (Ms) and remanent magnetization (Mr) of the samples increased with increasing of CoFe2O4 fraction. The increasing of Ms and Mr of composites indicated the strong dependence of magnetic properties on CoFe2O4 addition. [ABSTRACT FROM AUTHOR]

In this report, solid solutions of (1−x)Bi1/2Na1/2TiO3+xSrNiO3-δ materials were synthesized by a chemical method. X-ray diffraction and Raman scattering were used to study the structural properties of the (1−x)Bi1/2Na1/2TiO3+xSrNiO3-δ solid solutions. All studied samples had rhombohedral symmetry, where the Sr and Ni cations tended to randomly incorporate with the host Bi1/2Na1/2TiO3 lattices during the formation of solid solutions. The random incorporation of Sr and Ni cations into the host lattices resulted in structural distortion and reduced the optical band gap from 3.04 eV for the pure Bi1/2Na1/2TiO3 to 2.63 eV for the 9 mol.% SrNiO3-δ-modified Bi1/2Na1/2TiO3 sample. The complex magnetic properties of (1−x)Bi1/2Na1/2TiO3+xSrNiO3-δ system were investigated as a function of SrNiO3-δ concentrations. We expected that our simple and flexible method could be used to integrate the ferromagnetic properties in current advanced functional lead-free materials. [ABSTRACT FROM AUTHOR]

New solid solution (1−x)Bi1/2Na1/2TiO3+xBaNiO3−δ materials were synthesized by a chemical method. The X-ray diffraction and Raman scattering structure studies confirmed that the BaNiO3−δ materials were well soluted in the host Bi1/2Na1/2TiO3 materials. The random incorporation of Ba and Ni into the host Bi1/2Na1/2TiO3 materials was displayed by the optical properties where the optical bandgap values were reduced, and the photoluminescence was suppressed. The complex magnetic properties of Bi1/2Na1/2TiO3 materials were obtained as a function of BaNiO3−δ amounts in the solid solutions. The role of co-modification of A- and B-sites via alkaline earth metals and transition metals as substitution and interstitially on magnetic properties of Bi1/2Na1/2TiO3 materials was experimentally proposed, which is further supported by first-principles density functional theory calculations. We expected that our work provided a new method to inject the ferromagnetic properties in lead-free ferroelectric materials for smart electronic applications. [ABSTRACT FROM AUTHOR]

In this work, new complex binary solid solution (1−x)Bi1/2Na1/2TiO3 + xMgNiO3−δ materials had been synthesized by sol–gel method. Random incorporation of Mg and Ni cations into the host Bi1/2Na1/2TiO3 lattices resulted in a distortion of lattice parameters and reduced the optical bandgap. The optical bandgap was estimated at approximately 3.06 eV for the pure Bi1/2Na1/2TiO3 material and decreased to 2.82 eV for the 9 mol.%-MgNiO3−δ solid solution. The complex magnetic behaviors of the (1−x)Bi1/2Na1/2TiO3 + xMgNiO3−δ systems were achieved as a function of MgNiO3−δ amounts. The tunable magnetic properties of Bi1/2Na1/2TiO3 through MgNiO3−δ concentration control were important for integrating ferromagnetism into the lead-free ferroelectric Bi1/2Na1/2TiO3 materials. We expected our method to provide an important technique to tailor magnetic properties in lead-free ferroelectric materials for smart electronic applications. [ABSTRACT FROM AUTHOR]

NiTiO3 rods have been synthesized and the influence of pH on their photocatalytic activity under light-emitting diode (LED) irradiation investigated. Ilmenite NiTiO3 rods were synthesized by an ethylene glycol-mediated route at room temperature, followed by calcination in air. The samples were characterized using x-ray diffraction analysis, scanning electron microscopy, ultraviolet–visible (UV–Vis) spectroscopy, and photocatalytic methods. Photocatalytic degradation of rhodamine B was carried out using NiTiO3 rods under LED visible-light irradiation. The synthesized NiTiO3 rods were in pure rhombohedral phase after calcination at 600°C for 2 h. The rods were formed from small nanoparticles of about 30 nm with porous structure. The NiTiO3 rods presented a visible absorbance response and could degrade RhB dye under visible-light irradiation. The results reveal that pH plays an important role in the photocatalytic activity of NiTiO3. The results for the removal efficiency of RhB pollutant at pH values from 1 to 11 showed a maximum at pH 3. [ABSTRACT FROM AUTHOR]

A combined study of scanning tunneling microscopy (STM) and angle-resolved photoemission spectroscopy (ARPES) is conducted to understand the multiple charge density wave (CDW) phases of monolayer (ML) VSe2 films manifested by graphene substrates. Submonolayer (∼0.8 ML) VSe2 films are prepared on two different substrates of single-layer graphene (SLG) and bi-layer graphene (BLG) on a 6H-SiC(0001). We find that ML VSe2 films are less coupled to the SLG substrate compared to that of ML VSe2/BLG. Then, ML VSe2 grown on SLG and BLG substrates reveals a very different topography in STM. While ML VSe2/BLG shows one unidirectional modulation of √3 × 2 and √3 × √7 CDW in topography, ML VSe2/SLG presents a clear modulation of 4 × 1 CDW interfering with √3 × 2 and √3 × √7 CDW which has not been previously observed. We explicitly show that the reciprocal vector of 4 × 1 CDW fits perfectly into the long parallel sections of cigar-shaped Fermi surfaces near the M point in ML VSe2, satisfying Fermi surface nesting. Since bulk VSe2 is also well-known for the 4 × 4 × 3 CDW formed by Fermi surface nesting, the 4 × 1 CDW in ML VSe2/SLG is attributed to the planar projection of 4 × 4 × 3 CDW in bulk. Our result clarifies the nature of the 4 × 1 CDW in ML VSe2 system and is a good example demonstrating the essential role of substrates in two-dimensional transition metal dichalcogenides. [ABSTRACT FROM AUTHOR]

New solid solution of Na0.5Bi0.5TiO3 with BaFeO3−δ materials were fabricated by sol–gel method. Analysis of X-ray diffraction patterns indicated that BaFeO3−δ materials existed as a well solid solution and resulted in distortion the structure of host Na0.5Bi0.5TiO3 materials. The randomly incorporated Fe and Ba cations in the host Na0.5Bi0.5TiO3 crystal decreased the optical band gap from 3.11 to 2.48 eV, and induced the room-temperature ferromagnetism. Our density-functional theory calculations further suggested that both Ba for Bi/Na-site and Fe dopant, regardless of the substitutional sites, in Na0.5Bi0.5TiO3 lead to the induced magnetism, which is illustrated in terms of the exchange splitting between spin subbands through the crystal field theory and Jahn–Teller distortion effects. Our work proposes a simple method for fabricating lead-free ferroelectric materials with ferromagnetism property for multifunctional applications in smart electronic devices. [ABSTRACT FROM AUTHOR]

The NiTiO3 ceramic was synthesized in nanostructured form by citrate gel method. The phase structure, microstructure and magnetic properties of synthesized compounds were investigated by X-ray diffraction (XRD), scanning electron microscope and vibrating sample magnetometer. Williamson–Hall plot was used to calculate the crystallite size and microstrain of sample. The XRD analysis showed the formation of rhombohedral crystal structure of synthesized powders. The crystallite size is about 35 nm and microstrain is 5. 9 × 1 0 − 4 . The optical band gap was estimated from UV-Visible spectrum with value of 2.43 eV. The NiTiO3 samples showed coexistence of ferroelectric and antiferromagnetic properties at room temperature. [ABSTRACT FROM AUTHOR]

The (1 − x)Bi0.5Na0.5TiO3 + xCaCoO3−δ solid-solution system has been fabricated by a simple sol–gel route. X-ray diffraction analysis and Raman scattering measurements were performed to determine the structure of the solid-solution system. The samples were polycrystalline and had perovskite structure with rhombohedral symmetry. With increasing concentration of CaCoO3−δ solid solution in the host Bi0.5Na0.5TiO3, the optical bandgap reduced from 3.06 eV for pure Bi0.5Na0.5TiO3 to 2.15 eV for 9 mol.% CaCoO3−δ-modified Bi0.5Na0.5TiO3. This process also suppressed the photoluminescence of the host Bi0.5Na0.5TiO3. Weak ferromagnetism as well as diamagnetism were observed for pure Bi0.5Na0.5TiO3, changing to ferromagnetism and finally compensated ferromagnetism versus paramagnetism and/or antiferromagnetic-like behavior as the concentration of CaCoO3−δ was increased. Such introduction of ABO3 impurities containing alkaline-earth and transition metals into the host Bi0.5Na0.5TiO3 could therefore enhance the magnetic properties of this lead-free ferroelectric material to produce multiferroic materials for use in smart electronic devices. [ABSTRACT FROM AUTHOR]

The new solid solution system of (1 − x)Bi1/2Na1/2TiO3 + xBi(Ti1/2Co1/2)O3 materials was fabricated using the sol–gel method. The structural studies via X-ray diffraction and Raman scattering indicated that Bi(Ti1/2Co1/2)O3 materials were well dissolved into host Bi1/2Na1/2TiO3 materials to follow the rhombohedral structure of host materials. The diffuse cations of Bi(Ti1/2Co1/2)O3 to random incorporation with host lattice to form as solid solution in host Bi1/2Na1/2TiO3 materials resulted in distortion lattice parameter and reduced the optical band-gap values from 3.06 to 2.32 eV for pure and 9 mol% Bi(Ti1/2Co1/2)O3 solute into host Bi1/2Na1/2TiO3 materials. The compensative diamagnetism and weak ferromagnetism of pure Bi1/2Na1/2TiO3 materials were tuned to ferromagnetism at room temperature as increasing the Bi(Ti1/2Co1/2)O3 amounts solute into host Bi1/2Na1/2TiO3 materials. The observation of the room-temperature ferromagnetism in Bi(Ti1/2Co1/2)O3-modified Bi1/2Na1/2TiO3 system was important to integrate the ferromagnetic properties in lead-free ferroelectric materials for further application in smart electronic devices which were required multifunctional materials. [ABSTRACT FROM AUTHOR]

A new (1-x)Bi0.5Na0.5TiO3 + xMgCoO3-δ solid solution system was synthesized using the simple sol–gel method. The structure that was investigated via X-ray diffraction and Raman scattering analysis indicated that the MgCoO3-δ materials were highly soluble into the host Bi0.5Na0.5TiO3 crystals. The random incorporation of Mg and Co cations into the host crystal of the Bi0.5Na0.5TiO3 materials reduced the optical band gap energy and induced a complex magnetic behavior as a function of MgCoO3−δ concentration solute in the host matrix. The optical band gap energy values decreased from 3.05 eV for pure Bi0.5Na0.5TiO3 materials to 2.22 eV with 9 mol% MgCoO3-δ solution for the Bi0.5Na0.5TiO3 compounds. A weak ferromagnetic property with strongly induced diamagnetism was obtained at room temperature for the pure Bi0.5Na0.5TiO3 materials, whereas ferromagnetic properties were observed for the MgCoO3-δ-modified Bi0.5Na0.5TiO3 compounds. The addition of paramagnetic and/or antiferromagnetic-like behavior was obtained for the MgCoO3-δ solid solution with over 5 mol% in the host Bi0.5Na0.5TiO3 materials. This work contributes to the current understanding of the interaction of transition metal cations in the host crystal ABO3 perovskite of lead-free ferroelectric materials due to the co-modification of A and B sites. [ABSTRACT FROM AUTHOR]

(1 − x)Bi0.5Na0.5TiO3 + xSrCoO3−δ solid-solution system was synthesised through the simple sol–gel technique. X-ray diffraction and Raman scattering analyses were used to study the structure of (1 − x)Bi0.5Na0.5TiO3 + xSrCoO3−δ system. Results showed that the SrCoO3−δ materials dissolved well into the host Bi0.5Na0.5TiO3 crystal. The random incorporation of Sr and Co cations into the host Bi0.5Na0.5TiO3 crystal to form a solid solution resulted in reduced optical band-gap energy and induced the complex magnetic properties of host Bi0.5Na0.5TiO3 materials. The optical band-gap energy of pure Bi0.5Na0.5TiO3 materials was estimated to be approximately 3.09 eV, which decreased to 2.18 eV for 9 mol% SrCoO3−δ solute incorporated into Bi0.5Na0.5TiO3 materials. The magnetic properties of Bi0.5Na0.5TiO3 materials were tuned as a function of SrCoO3−δ concentration added into the host Bi0.5Na0.5TiO3 materials. The enhanced magnetic performance in SrCoO3−δ-modified Bi0.5Na0.5TiO3 materials can be possibly applied in multifunction materials for electronic devices. [ABSTRACT FROM AUTHOR]

CuPt nano alloy-particles were successfully synthesized by a combination of the methods of bipolar electrolytic and galvanic replacement. Cu2O nanoparticles prepared by a bipolar electrolytic method were used as the sacrificial templates for galvanic replacement reactions with H2PtCl6 solutions. The size of Cu2O nanoparticles was optimized by changing the electrolytic parameters to obtain fine nanoparticles. SEM and TEM analyses showed that Cu2O nanoparticles were grown in a crystal shape with a grain size of about 100 nm. The XRD results indicated that Cu2O nanoparticles were grown in a face-centered cubic structured crystal. The effects of the amount of H2PtCl6 solution on the structure, morphology, composition and electrocatalysis of CuPt were investigated. The phase analysis by XRD showed the presence of CuPt crystalline phases with a rhomb-centered structure. The SEM images indicated that the crystalline shape of Cu2O was turned into a spherical shape with the size expanded to 140 nm after galvanic reaction. The absorption analysis showed that there was one absorption peak at a wavelength of 500 nm for Cu2O while no absorption peak was observed for CuPt alloys. Additionally, compositional analysis by EDX showed that the main components of the alloys were Cu and Pt. The presence of O on the samples indicated that the galvanic reactions were not complete. The cyclic voltammetry measurement showed that CuPt nano alloy-particles exhibit better ethanol oxidation in an alkali medium compared with bare Pt. [ABSTRACT FROM AUTHOR]

Nickel titanate (NiTiO3) nanopowders have been synthesized using the sol-gel method. The effect of annealing temperatures on the structural, optical, and visible-light photocatalytic properties of the synthesized NiTiO3 nanopowders was investigated. The nanopowders annealed at a low temperature (500-600°C) showed a mixture of NiO, anatase, rutile, and NiTiO3. The TiO2 and NiO phases decreased with increased calcination temperature and transformed to NiTiO3 phase at a temperature higher than 600°C. The particle size of the prepared samples substantially increased with increased annealing temperature. The reduction of the optical band gap from 2.46 eV to 2.31 eV corresponded to the increase in annealing temperature from 500°C to 900°C, respectively. The NiTiO3 nanopowders annealed at 500°C exhibited high efficiency in the photodegradation of congo red dye under visible light irradiation. [ABSTRACT FROM AUTHOR]

Multiferroic materials based on lead-free ferroelectric materials have potential applications in the fabrication of next-generation devices. Herein, the sol-gel method is used to synthesize pristine and Cr-doped Bi0.5K0.5TiO3 nanocrystals. Density functional theory simulation is performed to elucidate the mechanism underlying the observed electronic and magnetic properties of the nanocrystals. In materials doped with 9 mol% Cr, the substitution of Cr in the Ti site decreases the optical band gap from 3.09 eV to 2.26 eV and induces ferromagnetism at room temperature. The saturation magnetization of the materials is approximately 0.18 μB/Cr at 5 K and can be attributed to the interplay of the unpaired electron counts of Cr3+ ions in the crystal field mechanism and Jahn-Teller effect. Pristine Bi0.5K0.5TiO3 samples exhibit weak ferromagnetism at room temperature, given the existence of the mixed valence states of Ti4+ and Ti3+ and the formation of O or Ti vacancies during sample growth. The present study provides deep insight into the induction of magnetism in ferroelectric materials doped with transition metals. Such materials have potential spintronic applications. The Cr-doped Bi0.5K0.5TiO3 materials were fabricated by the sol-gel method.The room-temperature ferromagnetism in Cr-doped samples was obtained.Optical band gap was reduced from 3.09 eV to 2.26 eV.Defect-induced room-temperature ferromagnetism was investigated by density functional theory calculations. [ABSTRACT FROM AUTHOR]

Pb-free ferroelectric solid solution of Bi0.5K0.5TiO3 with BiCoO3 has been fabricated using a sol-gel technique, exhibiting room-temperature ferromagnetism. The optical bandgap of Bi0.5K0.5TiO3 reduced from 3.21 eV to 1.77 eV with increasing amount of BiCoO3 solid solution. The room-temperature ferromagnetism and bandgap reduction occurred due to BiCoO3 diffusion into Bi0.5K0.5TiO3, resulting in formation of solid solution. These results provide a simple approach to realize room-temperature ferromagnetism in Pb-free ferroelectric materials. [ABSTRACT FROM AUTHOR]

We report the fabrication and characterization of surface acoustic wave (SAW) hydrogen sensors using palladium-graphene (Pd-Gr) nanocomposite as sensing material. The Pd-Gr nanocomposite as sensing layer was deposited onto SAW delay line sensor-based interdigitated electrodes (IDTs)/aluminum nitride (AlN)/silicon (Si) structure. The Pd-Gr nanocomposite was synthesized by a chemical route and deposited onto SAW sensors by air-brush spraying. The SAW H2 sensor using Pd-Gr nanocomposite as a sensing layer shows a frequency shift of 25 kHz in 0.5% H2 concentration at room temperature with good repeatability and stability. Moreover, the sensor showed good linearity and fast response/recovery within ten seconds with various H2 concentrations from 0.25 to 1%. The specific interaction between graphene and SAW transfer inside AlN/Si structures yields a high sensitivity and fast response/recovery of SAW H2 sensor based on Pd-Gr/AlN/Si structure. [ABSTRACT FROM AUTHOR]

The effect of sintering temperature on the giant electric field-induced strain was observed in lead-free Bi0.5(Na0.77Li0.05K0.18)0.5(Ti0.975Ta0.025)O3ceramics. The grains size and dense structure increased with increasing of the sintering temperature. The growth of polar phases was observed in non-polar phase when sintering temperature increased. The giant electric field-induced strain strongly enhanced up to Smax/Emax= 800 pm/V, resulting from coexistence of polar and non-polar phases. The highest values of Smax/Emaxwere higher than those were previously reported on non-textured lead-free piezoelectric ceramics. [ABSTRACT FROM AUTHOR]

Epitaxial ferromagnetic Mn5Ge3 thin films were stabilized on GaSb(001) and GaAs(001) substrates using molecular beam epitaxy. Compared to bulk Mn5Ge3 materials, an enhancement of the Curie temperature above 350 K and about 320 K was observed for Mn5Ge3/GaAs(001) and Mn5Ge3/GaSb(001) heterostructures, respectively. The magnetization was found to decrease from 323 to 245 emu/cm3 for films grown on GaSb(001) and GaAs(001). Anomalous Hall effect measurements provide evidence of the strain-induced large spin polarization from density-functional study. Furthermore, our calculated results in bulk Mn5Ge3 under strain indicate that the strain is the origin of different physical properties of Mn5Ge3 grown on different substrates. [ABSTRACT FROM AUTHOR]

An amendment to this paper has been published and can be accessed via a link at the top of the paper. [ABSTRACT FROM AUTHOR]

The new Bi0.5Na0.5TiO3-SrMnO3−δ solid solution materials were fabricated via sol–gel method. The random incorporation of Sr and Mn cations into host lattice of Bi0.5Na0.5TiO3 resulted in structural distortion and influenced on the reduction of the optical band gap from 3.07 eV to 1.81 eV for pure Bi0.5Na0.5TiO3 and 9 mol% SrMnO3−δ solid solution into Bi0.5Na0.5TiO3. The magnetic properties of Bi0.5Na0.5TiO3 materials at room temperature were tuned via compensation of diamagnetic material with weak-ferromagnetism to ferromagnetism with low SrMnO3−δ content and combination of paramagnetism/antiferromagnetism-like and ferromagnetism with higher SrMnO3−δ content solid solution in Bi0.5Na0.5TiO3. The tunable magnetic and optical properties of lead-free ferroelectric materials was promising for their application to green electronic devices. [ABSTRACT FROM AUTHOR]

We have newly synthesized the α-Mn structured Mn3Ge thin films on GaAs(001) substrate. The single phase Mn3Ge film was grown at a growth temperature of 150 °C, while the secondary phase was observed above a growth temperature of 250 °C. The Mn3Ge films exhibited ferrimagnetism with a Curie temperature of 334 K. The saturation magnetizations were 255.9 and 313.8 emu/cm3 and the corresponding coercive fields were 453 and 1166 Oe at 10 K for the samples grown at 150 and 300 °C, respectively. The ferrimagnetism was confirmed by the anomalous Hall effect data. [ABSTRACT FROM AUTHOR]

A solid solution of NiTiO3 in Bi0.5Na0.5TiO3 materials was fabricated by sol-gel technique. According to the X-ray diffraction analysis, (1 − x)Bi0.5Na0.5TiO3 + xNiTiO3 materials exhibited a rhombohedral structure following the Bi0.5Na0.5TiO3 crystal symmetry. The random distribution of Ni cations into the host lattice of Bi0.5Na0.5TiO3 materials decreased the optical band gaps from 3.06 to 2.74 eV for 9 mol.% NiTiO3 solid solution. The magnetic properties of Bi0.5Na0.5TiO3 materials were tuned from weak ferromagnetism to ferromagnetism and of compensation of ferromagnetism with diamagnetic and/or antiferromagnetic property. This work provides understanding of the role of exchange interaction of cation transition metals to integrate magnetic properties in lead-free ferroelectric materials for smart multifunctional electronic devices. [ABSTRACT FROM AUTHOR]