Investigations on structural and electrical properties of La³⁺ doped Ni_0.5Zn_0.5La_xFe_2−xO₄ nanoparticles

V. Kumar¹ - A. Rana² - O. P. Thakur²

¹ Department of Physics, DCR University of Science & Technology, Murthal, Sonepat, Haryana, India
² Netaji Subhas Institute of Technology, University of Delhi, Sector-3, Dwarka, New Delhi 110078, India

Abstract
Magnetic nanoparticles of Ni_0.5Zn_0.5La_xFe_2−xO₄ (with x = 0, 0.05, 0.10, 0.15, 0.20) have been synthesized by a chemical coprecipitation method. The synthesized nanoparticles were annealed at 300\degC and 600\degC for two hours to improve crystalline properties. X-ray diffraction (XRD) patterns confirm the single crystalline phase formation of Ni_0.5Zn_0.5La_xFe_2−xO₄ nanoparticles. Scherrer’s formula has been used to find the average crystallite size. Electrical properties of the Ni_0.5Zn_0.5La_xFe_2−xO₄ ferrite nanoparticles were studied on sample pallets with different La³⁺ ion concentration in the frequency range 100 Hz - 1 MHz using an impedance analyzer. It was found that the electrical conductivity increased with the increase in doping of La³⁺ ions as well as with frequency. Ferrofluids made from this type of rare earth ion-doped spinel ferrite nano-materials show the increased electrical conductivity. The decrease in D.C. resistance of Ni_0.5Zn_0.5La_0.2Fe_1.8O₄ with the increase in temperature shows the semiconducting nature of nano-ferrite materials. Tables 1, Figs 4, Refs 23.