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Multiferroic magnetoelectric composites are beneficial in device fabrication because of their tunable ferroelectricity and magnetism. The partial substitution in bismuth ferrite (BiFeO3) is one of the best possible ways for synthesizing pure phase BiFeO3-based materials. A comprehensive study of (1 − x)Bi0.85La0.15FeO3–xBaTiO3 (x = 0–0.3) was done by coalescing ferroelectric, dielectric, magnetic, and magnetoelectric properties with structural and microstructural characterizations to explore the effect of BaTiO3 (BT) into Bi0.85La0.15FeO3 (BLFO) and forming composite ceramics. The X-ray diffraction study reveals the phase purity in BLFO and a structural transformation from rhombohedral to cubic phase with increasing content of BT. The Raman spectroscopy and scanning electron micrographs confirm the co-existence of composite formation in BLFO–xBT. The Raman modes shift towards lower wavenumber with increasing BT concentration suggests lattice compression. The room temperature M–H hysteresis curve shows the existence of weak ferromagnetism in BLFO–BT composites and superparamagnetism in BLFO–10BT ceramic. The curve fitting of M–H curve for BLFO–10BT showed the existence of superparamagnetic particles. The ferroelectric hysteresis P–E loop measurements produced unsaturated oval-shaped loops with high leakage and displayed a lossy dielectric nature. The effect of magnetic field on polarization versus electric field curve reveals the interfacial interaction due to the origin of magnetoelectric interaction in BLFO–BT composite ceramics. All the samples display peak broadening in temperature–permittivity plot and confirm relaxor behavior. The superparamagnetic behavior and magnetic field-dependent energy storage capacity of BLFO–10BT composite ceramic make this material a potential candidate for magnetoelectric devices. [ABSTRACT FROM AUTHOR]

In this study, the effect of ZnO buffer layer on the electrical properties of PbZrTiO3/BiFeO3 (PZT/BFO) multilayers has been reported. For this, PZT/BFO multilayers were spin-coated with and without ZnO buffer layer on platinized silicon wafers. X-ray diffraction results of both the films showed polycrystalline phase pure perovskite structure. Both the films show a dense and homogeneous grain structure. The electric properties of the films were measured. The ZnO buffered multilayer thin film showed ∼3 times improvement in remnant polarization compared to the multilayer thin film with no buffer. The buffered samples were found to have higher dielectric constant (1000 at 100 Hz) compared to that of sample (580 at 100 Hz)) with no buffer. Dielectric constants of both the films were found to be ∼30% tunable at 5 V. The buffered film also showed low leakage current density and higher dielectric breakdown compared to the multilayer thin film without buffer. [ABSTRACT FROM AUTHOR]

(1-x)BiFe0.75Mn0.25O3-(x)BaTiO3 (x = 0.1, 0.2, 0.3) solid solutions have been prepared utilizing conventional solid state reaction route. Powder XRD study confirmed the structural evolution from rhombohedral to cubic phase with an incorporation of BaTiO3 (BT). Further insight in to microstructure revealed structural bonding using FTIR spectra and reduced grain size and shape along with reduced porosity with an increasing BT content using SEM studies. Maximum polarization of 56 μC/cm2 was observed for x = 0.3. The magnetoelectric coupling coefficient was obtained successfully by straight line fitting of induced polarization vs. magnetic field graph and was found to be 0.83124 μC/cm2/T. [ABSTRACT FROM AUTHOR]

BiFeO3-CoFe2O4 composites were successfully prepared via conventional solid state method. Powder X-ray diffraction confirmed the presence of both perovskite BiFeO3 (BFO) and spinel CoFe2O4 (CFO) phases and rhombohedral structure due to splitting in major peaks in the composites. Further insight into the microstructural and morphological properties of the composites was provided by Raman spectra, Fourier Transform Infrared Spectroscopy and Field Emission Scanning Electron Microscopy along with EDX analysis. Magnetic and electrical response of the composites has been studied exhaustively to comprehend their multiferroic properties. Magnetization study (magnetization vs. magnetic field) confirmed the high saturation magnetization in composites with a low value of coercivity at room temperature. The maximum saturation magnetization (0.3902 emu/g) was achieved in BFO-30%CFO. Ferroelectric polarization (polarization vs. electric field) loop measurements confirmed the low electrical leakage current in the composites. The temperature dependent dielectric response of the composites suggested existence of magnetoelectric coupling between the ferroelectric and ferromagnetic orders in the vicinity of antiferromagnetic-paramagnetic transition temperature of BFO. The decrease in dielectric loss with an increase in CFO content in the composites also validated the similar results as observed in polarization versus electric field measurements. The Impedance Spectroscopy at room temperature revealed the non-Debye behavior and high resistivity of the composites. [ABSTRACT FROM AUTHOR]

Samples of CaCu3Ti4O12 (CCTO) ceramics were prepared by solid state reaction method. X-ray diffraction analysis confirmed single phase formation for the powder calcined at 1173 K. Sintering was done at different temperatures viz. 1348 K, 1373 K and 1398 K with a fixed heating rate of 3 K/min. Detailed study of dielectric properties was carried out for the CCTO samples sintered at 1373 K for different duration of holding times (2 h and 10 h). It is found that dielectric properties are sensitive to both sintering time and temperature. With increasing sintering time from 2 h to 10 h dielectric constant increases from ∼2.1 × 104 to ∼2.5 × 104 measured at 1 kHz at room temperature. Impedance spectroscopy has been used for separating out of grain and grain boundary contributions to the overall electrical properties. [ABSTRACT FROM AUTHOR]

Modified Lead Calcium Titanate (PCT) compositions with representative formula, Pb 0.76 - x Sm x Ca 0.24 Ti 0.98 Mn 0.02 O 3 (x = 0–0.1 in steps of 0.02) were prepared by conventional dry ceramic method. Effects of samarium substitution on physical, structural properties and thermal behaviour of PCT ceramics are reported here. All the samples were subjected to XRD analysis and were found to have single phase with tetragonal structure up to 8 mol% Sm substitution. The variations of density and tetragonality have been studied with samarium content. Microstructural analysis shows the uniform grain growth with increasing Sm concentration. Dilatometric study has been done to predict sintering schedule of the green samples. [ABSTRACT FROM AUTHOR]

Various glasses in the system (65 − x)[SrO · TiO2]-(35)[2SiO2 · B22O3]-( x)La2O3, where x = 1,5,10 (wt%) were prepared by melting in alumina crucible (1375–1575 K). Heat treatment schedules were selected from DTA plots of respective glasses. X-ray diffraction studies of glass ceramic samples containing different concentrations of La2O3 revealed the formation of Sr2B2O5, Sr3Ti2O7 and TiO2 (rutile) phases. The addition of La2O3 results in the development of well formed, elongated crystallites of different phases. Results of the dielectric behaviour demonstrate higher values of dielectric constant for some of the glass ceramic samples. This can be ascribed to the relaxation polarization at the crystal-glass interface due to conductivity differences between crystalline and glassy phases. [ABSTRACT FROM AUTHOR]