Modulation the structural, magnetic and electrical properties of Ni‐Zn ferrites by lutetium substitution

Ni-Zn ferrites with a formula of Ni 0.5 Zn 0.5 Lu x Fe 2− x O 4 ( x = 0.000, 0.004, 0.008, 0.012, 0.016 and 0.020) have been synthesized by ceramic sintering method. The effects of Lu 3+ doping on structural, electrical and magnetic performances are investigated. X-ray powder diffraction results demonstrate that Lu 3+ ions completely enter into the lattice of cubic spinel structure without formation impurity phases. By increasing Lu 3+ content, the lattice parameter increases monotonously. The average crystallite size D and microstrain for all samples are estimated by Williamson-Hall (W-H) method. Fourier transform infrared spectroscopy (FTIR) and energy dispersive spectra (EDS) analyses confirm the cubic spinel phase and chemical composition of the as-synthesized Ni 0.5 Zn 0.5 Lu x Fe 2− x O 4 , respectively. Scanning electron microscope (SEM) images indicate that the size of agglomerated particles is not uniform with a little bit of pores, and the grain boundaries become more ambiguous as increasing Lu 3+ content. The permittivity indicates a normal dielectric behavior of Ni-Zn ferrites under the alternating electric field. However, when the frequency of applied electric field reaches a certain value, the dielectric loss tangent will appear a peak behavior. The typical ferromagnetic S-shape loops of these samples were collected by vibrating sample magnetometer (VSM), the saturation magnetization first increases and then decreases with increasing Lu 3+ concentration, exhibiting a maximum value of 71.41 emu/g when x = 0.004.