Enhanced transport, dielectric and magnetic properties of Ni-doped (YFeO3)0.5(BaTiO3)0.5 perovskite for NTC thermistor and multifunctional applications

Abstract

The solid-state reaction method was successfully employed to synthesize the environmentally friendly polycrystalline perovskite (Y_0.5Ni_0.5FeO₃)_0.5(BaTiO₃)_0.5. X-ray diffraction (XRD) analysis, complemented by Rietveld refinement, confirms its multiphase crystalline structure, comprising two cubic and one orthorhombic phase. Field-emission scanning electron microscopy (FE-SEM) reveals a well-defined surface morphology, while energy-dispersive spectroscopy (EDS) and elemental mapping validate the homogeneous distribution of constituent elements. Raman and FTIR spectroscopy further confirm the vibrational and atomic structural integrity of the material. Dielectric studies indicate a high dielectric constant (∼338 at 100 Hz, room temperature), with strong frequency and temperature-dependent relaxation effects. Impedance spectroscopy reveals non-Debye relaxation behaviour, NTCR characteristics and impedance in the megaohm range at lower temperatures. AC conductivity results align well with Jonscher's power law. The thermistor coefficient (β) reaches 4778.61 at 450 °C, demonstrating excellent potential for thermistor applications. Magnetic studies confirm a prominent ferromagnetic response at room temperature, with a saturation magnetization of 3.654 emu g⁻¹ and coercive field of 196.4 Oe. These combined properties make (Y_0.5Ni_0.5FeO₃)_0.5(BaTiO₃)_0.5 a promising candidate for multifunctional applications.