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In this report, we have investigated the effect of BaTiO3 on the preliminary structural analysis, ferroelectric phase transition and electrical properties of (1 − x) P b (F e 0.5 N b 0.5 ) O 3 − x B a T i O 3 (P F N − B T) (x = 0 , 0.025 , 0.05, and 0.1) solid solutions. Conventional solid-state reaction technique is adopted to synthesize P F N − B T solid solution. X-ray diffraction (XRD) analysis is used to study the preliminary structural analysis, which suggests the formation of the single-phase materials. The surface morphology is studied using field emission scanning electron microscope (FESEM). The temperature-dependent dielectric properties display a broad diffuse phase transition from ferroelectric to paraelectric state and the phase transition temperature was found to be decreased with an increase in BT concentrations. Ferroelectric property of the solid solutions is confirmed by the polarization vs. electric field (P–E) loops study at room temperature. Variation of AC conductivity with frequency and temperature is also studied. The addition of BT leads to a decrease in the dielectric loss and phase transition temperature. [ABSTRACT FROM AUTHOR]

Spinel ferrites have been widely studied due to their remarkable properties such as high saturation magnetisation, large magnetic permeability, and high electrical resistivity. Among the oxides-based magneto strictive spinel ferrite, CoFe2O4 (CFO) possess the highest value of absolute magnetostriction coefficient (–110 ppm). But CFO has the disadvantage of large magnetic anisotropy and high coercivity. Therefore, doping of zinc (Zn) at Co-site of CFO is reported to reduce the magnetic coercivity and increases the resistivity (108Ω) keeping the magnetostriction coefficient with a sizable value. Also, substitution of Zn for Co in CFO reduces magnetic anisotropy. So, in view of this we have prepared Zn modified CFO compound: Co0.9Zn0.1Fe2O4 using sol-gel combustion technique. The room temperature (RT) XRD patterns indicate the formation of single-phase material without appearance of any impurity phases within the detection limit of X-ray diffractometer. The Rietveld refinement on the RT XRD pattern of CZFO sample was carried out using cubic crystal structure with space group Fd-3m. A good agreement between the experimental and the fitted data has been observed. The average crystallite size for the composition was calculated from the XRD patterns using Williamson–Hall method. Scanning electron micrographs displays homogeneous distribution of grains throughout the sample microstructure with the presence of minute amount of pores. The dielectric and electrical properties were studied as function of frequencies at different temperatures. Complex impedance spectroscopic technique study on this sample suggests existence of non-Debye type dielectric relaxation behaviour. [ABSTRACT FROM AUTHOR]

Highlights • Acrylamide polymer gel template method has been used to prepare single phase DyMnO 3. • Heat capacity measurement shows three transitions due to T N (Dy), T lock and T N (Mn). • Magnetic field strongly affect T N (Dy) and T lock as observed in heat capacity data. • The magnetic study reveals the presence of two transitions due to T N (Dy) and T lock. • Increase in weak ferromagnetic behaviour with decrease in temperature. Abstract Single phase polycrystalline DyMnO 3 (DMO) was synthesized using acrylamide polymer gel template method. We report the structural, magnetic, specific heat and dielectric properties of DMO over wide experimental conditions. Room temperature XRD pattern shows the formation of singe phase material without any impurity. The magnetic properties such as magnetization versus temperature (M vs. T) and magnetization versus magnetic field (M vs. H) were studied around the transition temperatures region. The temperature dependent magnetization data suggest two phase transitions corresponding to the lock-in temperature below which ferroelectric ordering exist (around 19 K; T lock) and antiferromagnetic (AFM) ordering of Dy spin (around 8 K; T N (Dy)). The magnetic hysteresis obtained were fitted to extract weak ferromagnetic (FM) and antiferromagnetic/paramagnetic (AFM/PM) contribution to the magnetic data. The order of magnetic transitions were analyzed from Arrott plot. The temperature dependent specific heat measurement shows all three phase transitions corresponding to (i) AFM ordering of Mn spin (around 38 K; T N (Mn)), (ii) T lock transition and (iii) T N (Dy) transition. The effect of magnetic field to the transitions were studied using specific heat capacity measurement. The peak intensity of T N (Dy) decreases on the application of magnetic field whereas peak intensity of T lock increases with increase in magnetic field in specific heat measurement. Further the third anomaly, T N (Mn) remains more or less unaffected by the application of magnetic field. The intrinsic dielectric behaviour of the material was observed up to 160 K, above this temperature there is large increase in dielectric value due to the contribution from Maxwell- Wagner polarization. [ABSTRACT FROM AUTHOR]