Structural, magnetic and dielectric properties of (Li1+, Al3+) co-doped Ni0.5Zn0.5Fe2O4 ferrite ceramics prepared by the sol-gel auto-combustion method

(Li1+, Al3+) co-doped Ni0.5Zn0.5Fe2O4 ferrites, Ni0.5-xZn0.5-xLixAlxFe2O4 (x = 0.000, 0.025, 0.050 and 0.100), were synthesized by the sol-gel auto-combustion method. X-ray diffraction (XRD), field emission scanning electronic microscope (FESEM), vibrating sample magnetometer (VSM) and LCR meter were used to investigate the structural, magnetic and dielectric properties. Results of XRD and SEM indicate that both doping amount and calcination temperature play significant roles in crystal structure and grain growth. Also, it can be observed that the saturation magnetization and the coercivity change in a noticeable manner. The Ni0.475Zn0.475Li0.025Al0.025Fe2O4 ferrite sintered at 1200 °C has a relatively low coercivity value (62.93 Oe) and the largest saturation magnetization (110.95 emu/g). Besides, dielectric behavior is also improved by Li1+ and Al3+ co-doping.