Structural, dielectric, ferroelectric (FE), 119Sn Mössbauer, and specific heat measurements of polycrystalline BaTi1–xSnxO3 (x = 0% to 15%) ceramics are reported. Phase purity and homogeneous phase formation with Sn doping is confirmed from x-ray diffraction and 119Sn Mössbauer measurements. With Sn doping, the microstructure is found to change significantly. Better ferroelectric properties at room temperature, i.e., increased remnant polarization (38% more) and very low field switchability (225% less) are observed for x = 5% sample as compared to other samples and the results are explained in terms of grain size effects. With Sn doping, merging of all the phase transitions into a single one is observed for x ≥ 10% and for x = 5%, the tetragonal to orthorhombic transition temperature is found close to room temperature. As a consequence better electro-caloric effects are observed for x = 5% sample and therefore is expected to satisfy the requirements for non-toxic, low energy (field) and room temperature based applications.

The authors find that for mechanically milled Ni0.5Zn0.5Fe2O4 (∼10 nm), the mechanical strain induced enhancement of anisotropy energy helps to retain stable magnetic order. The reduction of magnetization can be prevented by keeping the cation distribution of nanometric ferrites at its equilibrium ratio. Moreover, the sample can be used in coding, storing, and retrieving of binary bit (“0” and “1”) through magnetic field change.

It is shown that Ca2+ doping at Bi-site results in the release of weak ferromagnetism in BiFeO3. Structural transformation from rhombohedral to triclinic is observed with 10% Ca doping. Raman measurements show the presence of oxygen vacancies with Ca doping and no evidence of either intermediate valence or the tetravalence of iron is observed from Mössbauer measurements. No significant change in Neel temperature is observed with Ca doping. The observed weak ferromagnetism and ferroelectric nature at room temperature indicates the multiferroic nature of Bi1−xCaxFeO3 (x=5% and 10%) samples.

In this work a Mn doped magnetoelectric BiFeO 3 system is studied. Xray diffraction (XRD), scanning electron microscopy, energy dispersive xray analysis (EDX), Mössbauer spectroscopy at room and high temperatures, differential scanning calorimetry (DSC), high temperature magnetization, dielectric constant measurements and x-ray photoelectron spectroscopy (XPS) are used to characterize the samples. The XRD result shows BiFeO 3 as a major phase along with about 1-2% impurity phase. EDX shows the equi-atomic ratio of Bi and Fe site cations. Using DSC it is observed that the Néel temperature decreases with Mn doping. Using Mössbauer and XPS it is observed that Fe exists in the +3 oxidation state. The samples have an antiferromagnetic nature with Mn doping.

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