Investigation on the dielectric and magnetic properties of perovskite-spinel (KNbO3-NiFe2O4) composites

Abstract

In this work, (1-x)KNbO3-(x)NiFe2O4 (x=0.0, 0.25, 0.5, 0.75, and 1.0 mol.%) composites were synthesized using solid-state reaction method and their physical properties were described. X-ray diffraction, Raman and Fourier transform infrared spectroscopy revealed that the prepared composites have mixed phases of orthorhombic KNbO3 (KNO) and cubic NiFe2O4 (NFO). The surface morphology of the prepared samples significantly changed from a rod-like shape to agglomerated flake-like shape. The chemical state and the existence of K, Nb, Ni, Fe, and O elements in (1-x)KNO-(x)NFO samples were confirmed by X-ray photoelectron spectroscopy and energy dispersive X-ray analyses, respectively. The 0.25 KNO-0.75 NFO has a relatively higher dielectric constant (3.5 × 105) than that of individual KNO (1.45 × 103) and NFO (1.58 × 105) samples. The vibrating sample magnetometer results revealed that the saturation magnetization (Ms) varies between 0.22 and 32 emu g−1. A relatively large value of coercivity (Hc=325 Oe) was observed for the 0.75 KNO-0.25 NFO sample.