Cobalt가 치환된 NiZnCu ferrite의 소결 및 자기적 성질에 미치는 영향에 대해 연구 하였다. 칩인덕터용 Ni _{0.36 − x}Co_xZn_0.44Cu_0.22Fe_1.98O₄(0 ≤ x ≤ 0.04)를 고상반응법으로 제조하였다. 소결조제를 사용하지 않고 880~920 ^oC에서 공기중 2시간 열처리 하였으며 초투자율, 품질계수 Q, 밀도, 수축율, 포화자화, 및 보자력을 측정하였다. Cobalt가 치환된 NiZnCu ferrite는 품질계수 Q를 증가시켰으며 칩인덕터용으로 사용 가능함을 알 수 있었다. 품질계수 Q는 치환량이 x = 0.01까지 증가한 후 x = 0.01 이후로 급격히 감소하였다. Cobalt의 치환량이 증가함에 따라 초투자율 및 밀도값은 감소하였다. 900^oC에서 소성된 Ni_0.35Co _0.01Zn_0.44Cu_0.22Fe_1.98O₄ 토로이달 core 샘플의 경우 1 MHz에서 측정 시 초투자율값은 130이었고 품질계수 Q값은 230으로 나타났다.

Effect of cobalt substitution on the sintering behavior and magnetic properties of a NiZnCu ferrite was studied. Ni _{0.36 − x}Co_xZn_0.44Cu_0.22Fe_1.98O₄(0 ≤ x ≤ 0.04) ferrite was fabricated by a solid stat reaction method. It was proposed and experimentally verified that Co²⁺ substituted NiZnCu ferrite was effective on improving the quality factor and magnetic properties of NiZnCu ferrites for multilayer chip inductors. The ferrite was sintered without sintering aids, at 880~920 ^oC, for 2 h and the initial permeability, quality factor, density, shrinkage, saturation magnetization, and coercivity were also measured. The quality factor (Q)
was increased linearly up to x = 0.01 and decreased rapidly over x = 0.01. As the cobalt content increased, the initial permeability and density of the ferrites decreases. The initial permeability of toroidal sample for Ni_0.35Co _0.01Zn_0.44Cu_0.22Fe_1.98O₄ferrites sintered at 900 ^oC was 130 at 1 MHz and quality factor was 230.