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Multiferroic is the future of the next generation memory devices; because of its advantages over the single-phase ferroelectric and ferromagnetic memory systems. In conventional ferroelectric memory system fatigue effect lowers the storage capacity. Other side high magnetic energy is essential for writing the data in ferromagnetic-based memory system. Considering these facets and taking environmental issue in the account we developed lead-free Na0.5Bi0.5TiO3 (NBT)–CoFe2O4 (CFO) multiferroic system via two wet chemical methods. To check the feasibility of the system for device application various physical measurements were carried out. The structural analyses have been done by XRD, FTIR and FESEM which confirm the coexistence of bi-phase in these composites. The dense microstructure was observed for composite sample with highest CFO concentration. In comparison to pure ferrite phase, the composite exhibit low leakage current density, high dielectric constant with low dielectric losses. Interestingly, the CFO affected the phase transition temperature of the NBT as evidenced by the dielectric behaviour as a function of temperature. Also, multiferroic studies were influenced by the content of CFO/NBT phases in composite system. Furthermore, the highest value of ME coupling (~ 64 μV/Oe-cm) was observed for the 50CFO/50NBT composite system. [ABSTRACT FROM AUTHOR]

To realize multiferroic and magnetoelectric properties, bi-layered nanocomposite films consisting of CoFe2O4 (CFO)/Pb1-xSrxTiO3 (PST) phases (x=0.1, 0.2, and 0.3) have been deposited on Pt/TiO2/SiO2/Si substrate by using a metallo-organic decomposition process. Both the PST perovskite and the CFO spinel phases are confirmed from X-ray diffraction patterns and Raman spectra of the composite films. The composite films exhibit room temperature multiferroic properties. The values of saturation magnetization (Ms), remanent magnetization (Mr), and coercive field (Hc) of the composite films are in the range of 108-119 kA/m, 42-51 kA/m, and 44.5-64.1 kA/m, respectively. In addition, the saturation polarization (Ps), remanent polarization (Pr), and electrical coercive field (Ec) are observed in the range of 11.3-14.4 μC/cm², 2.9-4.8 μC/cm², and 56-59.5 kV/cm, respectively. The dielectric response in the presence of applied magnetic field, Hdc∼238.6 kA/m shows a high magnetocapacitance value ∼385% at frequency 100 kHz for CFO/PST composite film with x=0.1. The maximum magnetoelectric voltage co-efficient value, αE∼380 kV/(m×T) has been achieved in the composite films with x=0.1. The influence of elastic/and or interfacial strain on multiferroic magnetoelectric properties is evident from the results. [ABSTRACT FROM AUTHOR]

This article describes preparation of Barium (Zirconium) Titnate (BaZr0.2Ti0.8O3) ceramics by the sol–gel technique and its structural, dielectric, ferroelectric, and piezoelectric properties investigated with sintering temperature variation. The phase and microstructure analysis of the sintered ceramics was carried out by X-ray diffraction method (XRD) and scanning electron microscopy (SEM), respectively. XRD analysis revealed structural transformation from cubic to tetragonal phase with increase in sintering temperature. Dielectric properties have been measured with variation of frequency up to 1 MHz and with temperature up to 200 °C. The BZT ceramics exhibit diffuse phase transition with normal ferroelectric behavior. Hysteresis loop measurements disclosed that BZT ceramics have good ferroelectric nature with saturation at higher applied electric fields. Leakage current density show negative temperature coefficient resistance (NTCR) behavior. The highest value (261 pC/N) of piezoelectric coefficient (d33) has been obtained for BZT ceramic sintered at 1400 °C and revealed that ceramics have great potentials for electronic industry based on sensor technology. [ABSTRACT FROM AUTHOR]

Na0.5Bi0.5TiO3 (NBT) and CoFe2O4 (CFO) powders have been prepared by sol-gel and metallo – organic (MOD) chemical solution methods respectively. The lead-free 50NBT-50CFO multiferroic particulate composite has been prepared by mixing NBT and CFO powders in required stoichiometric concentration. The structural and microstructural properties of ferroelectric (NBT) and ferrite (CFO) phases have been studied by X-ray diffraction and field emission scanning electron microscopy micrographs. The M-H curve of 50NBT-50CFO confirms the ferromagnetic behavior of the composite. The ferroelectric properties are also investigated by measuring polarization vs. electric field (P-E) hysteresis loops. Electrical properties are also studied by Keithley 2611 Source Meter. [ABSTRACT FROM AUTHOR]

Lead free Ba0.7Ca0.3O3 (BCT) ceramic has been synthesized by sol-gel method. Properties of ceramics are studied at sintering temperatures of 850 °C and 1050 °C. Structural Confirmation done using X-ray diffraction (XRD), diffractions patterns confirm the perovskite kind of structure without any impurity phase even at sintering of 850 °C. Surface morphology is studied using Scanning Electron Micrograph (SEM). Reduction in porosity and improvement in density detected at annealing temperature of 1050 °C. Improvement has been observed in dielectric constant and reduction in dielectric losses. Further ferroelectric property and leakage current density are studied under dielectric and electric study. [ABSTRACT FROM AUTHOR]

High resistivity in nanostructured Pb(Fe0.012Ti0.988)O3 system prepared by using polyvinyl alcohol (PVA) in chemical route is observed. The PVA acts as a surfactant to limit the particle size. The Fe substitution for Ti controls the chemical stoichiometry and reduces the lattice distortion, i.e., c/a ratio, and hence the transition temperature reduces with Fe content. The phase structure, morphology, particle size, dc resistivity, and dielectric and magnetic properties of Pb(Fe0.012Ti0.988)O3 nanoparticles have been characterized by x-ray diffraction, transmission/scanning electron microscopy, source meter, LCR meter, and vibrating sample magnetometer. The results indicate that the nanosize particles have high resistivity, which improves the dielectric constant at high-frequency region and increases magnetization of the specimens. The observed variable-range-hopping conduction mechanism indicates that Fe doping leads to the occurrence of local defect states in the PbTiO3 lattice. The dispersionless dielectric properties with low loss are observed up to 15 MHz. The dielectric properties are improved than those obtained by the conventional process. The initial permeability values do not exhibit much variation up to ferromagnetic transition temperature after which it falls sharply. The large value of saturation magnetization is observed at room temperature. [ABSTRACT FROM AUTHOR]