본 연구에서는 졸겔법으로 Ni_xZn_{1 − x}Fe₂O₄(x = 0.4, 0.5, 0.6)를 합성하였다. 합성 온도가 400 ^oC 이상일 때 단상의 spinel 상이 합성되었으며, 온도가 400 ^oC에서 1000 ^oC로 증가함에 따라 입자 크기도 17.6 nm에서 96.2 nm로 증가하였다. 400 ^oC에서 합성한 Ni_xZn_{1 − x}Fe₂O₄(x = 0.4, 0.5, 0.6) 시료에 대해 1000 ^oC 및 1250 ^oC의 온도에서 각각 소결 공정을 진행하였다. 소결체에 대하여 BH curve 및 복소투자율 spectra를 측정하여 Ni 치환량 및 소결 온도에 따른 자기적 특성의 변화를 연구하였다.

Ni_xZn_{1 − x}Fe₂O₄(x = 0.4, 0.5, 0.6) spinel ferrites were prepared by sol-gel method using precursors of Ni(NO₃)₂· 6H₂O, Zn(NO₃)₂· 6H₂O, and Fe(NO₃)₂· 9H₂O. Crystalline spinel phase were confirmed by X-ray diffraction (XRD) analysis for all the samples synthesized at T ≥ 400 ^oC. Scanning electron microscope (SEM) was used for the study of microstructure. The average crystalline size increases from 17.6 nm to 96.2 nm with increasing synthesis temperature from 400 ^oC to 1000 ^oC for the Ni_0.5Zn_0.5Fe₂O₄. Sintering process was conducted at 1000 ^oC and 1250 ^oC, respectively, on Ni_xZn_{1 − x}Fe₂O₄ (x = 0.4, 0.5, 0.6) samples
synthesized at 400 ^oC. B-H curve and complex permeability measurements were performed on these samples and the effect of composition, sintering temperature on the magnetic properties were investigated.