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Bi0.85La0.15FeO3, a Lanthanum (La) modified form of bismuth ferrite (BFO) crystallizes to crystal structure which is free from any impurity, which improves the multiferroic properties of BFO. To achieve the enhanced multiferroic characteristics, the composition of Bi0.85La0.15FeO3 has been optimized with the Mn substitution which increases magnetization more effectively than those of magnetic cations. Therefore, Bi0.85La0.15Fe1−xMnxO3 polycrystalline samples were synthesized using a tartaric acid modified sol–gel technique for x = 0.000, 0.025, 0.050, and 0.100. The effects of substitution of Mn (non-magnetic in nature) at the Fe site on crystal structure, magnetic properties, and optical properties were then investigated. The formation of crystalline phases was checked by using X-ray diffraction. The structural transition from rhombohedral (R3c, space group) to orthorhombic (Pbnm, space group) is strongly supported by the Rietveld refinement of the XRD pattern as well as analysis of Raman spectra. As Mn substitution increases, the intensity of Raman peak at about 650 cm−1 increases as well, indicating an increase in the contribution of orthorhombic phase. Magnetic properties of Bi0.85La0.15Fe1−xMnxO3 polycrystalline samples were assessed at room temperature. In Bi0.85La0.15Fe1−xMnxO3, the Mn substitution at the Fe site produced the highest magnetic moment for x = 0.025. Magnetic hysteresis loops show a substantial change in the magnetization with the increase in Mn substitution. Using the Kubelka–Munk (K–M) function and Tauc plot, the band gap energies of all the samples were calculated from UV–Vis diffuse reflectance spectra and it was observed that the band gap energy decreases with the increase in Mn substitution in Bi0.85La0.15Fe1−xMnxO3. These findings provide better understanding for tuning of the multiferroic properties of Mn substituted Bi0.85La0.15FeO3 ceramics. [ABSTRACT FROM AUTHOR]

Incorporation of different types of nanofillers in the PVDF poly(vinylidene difluoride) matrix exhibits promising dielectric, magnetic, piezo, pyro, and ferroelectric properties for various applications. Hence a novel nanocomposite has been developed by using PVDF and cobalt ferrite (CFO) (CoFe2O4) with different particle size of CFO for dielectric applications. The nanocomposite has been characterized by the X‐ray diffraction pattern, atomic force microscopy, transmission electron microscopy, fourier transform infra‐red spectroscopy, field emission‐scanning electron microscopy), and dielectric measurements. The space charge effect at the PVDF and CFO interfaces offers the interfacial polarization in nanocomposite, which contribute to tune the dielectric response of nanocomposite along with low dielectric loss. The filler size has been optimized to have better formation of polar β phase in PVDF along with high dielectric properties. The dielectric constant in nanocomposite has increased three times compare to that of PVDF. The 20 ± 1 nm size (CFO) filler in PVDF matrix exhibits optimized dielectric properties. POLYM. COMPOS., 40:1239–1250, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Ho3+ion-substituted nanocrystalline cobalt ferrite materials with the chemical formula CoFe2−xHoxO4forx = 0.0, 0.025, 0.05, 0.075 and 0.1 have been synthesised by standard citrate precursor method. Crystal structure and phase purity have been studied by powder X-ray diffraction (XRD) method by employing Rietveld refinement technique. The distribution of cations between the tetrahedral site (A-site) and octahedral site (B-site) has been estimated by Rietveld analysis. The refinement result shows that Ho3+ion has a strong preference for octahedral sites (B-sites). The lattice constants decrease with the Ho3+concentration up tox = 0.05. Crystallite size decreases with the Ho3+concentration. The magnetic hysteresis loop measurements have been carried out at room temperature using a vibrating sample magnetometer (VSM) over a field range of ±2 T. The magnetisations in saturation have been analysed by employing the ‘law of approach (LA)’ technique. The magnetocrystalline anisotropy constant and saturation magnetisation are found to decrease with the Ho3+concentration up tox = 0.05. The coercivity decreases with the Ho3+concentration. The vibrational modes of the octahedral and tetrahedral metal complex in the sample have been carried out using Fourier transform infrared spectroscopy (FT-IR). The FT-IR spectra of the samples have been analysed in the wave number range of 350–1000 cm−1. We have observed two prominent absorption bands which are assigned to tetrahedral and octahedral metal complexes. The elemental analysis has been carried out using energy dispersive spectroscopy (EDS) with the help of field emission scanning electron microscope (FE-SEM) and the results reveal that, elements are as per the stoichiometric ratio in all the samples. [ABSTRACT FROM AUTHOR]