Abstract
Lithium ferrites are prominent in the element of microwave frequency communication core and high frequency memory core because of their low coercivity and the high squareness ratio. This paper reports primarily the development of lithium ferrites with the low coercivity and high squareness ratio. The materials with $Li_{0.48-0.5x}Bi_{0.02}Ni_{0.04}Zn_xFe_{2.46-0.5x}O_4$ (x = 0,0.01, 0.02, 0.03) have been prepared to investigate the physical properties. The addition of ZnO gave raised maximum induction $(B_m)$ and decreased coercive force $(H_c)$, but the squareness ratio $(R\;=\;B_m/B_r)$ was decreased. The specimen of squareness ratio R=0.82, coercive force $H_c=\;1.80\;Oe$ was obtained for $Li_{0.48-0.5x}Bi_{0.02}Ni_{0.04}Zn_xFe_{2.46-0.5x}O_4$ (X=0) sintered at 105$0^{\circ}C$. Also the sample of squareness ratio R = 0.75, coercive force $H_c=\;1.70\;Oe$ for $Li_{0.48-0.5x}Bi_{0.02}Ni_{0.04}Zn_xFe_{2.46-0.5x}O_4$ (X = 0) sintered at 110$0^{\circ}C$ was measured. The Tc was obtained 463$^{\circ}C$ and the Br of environmental temperature variation was stable.
각종 microwave용 통신기기 소자 및 고주파용 memory 소자로 사용하기 위해서 각형비가 크고 보자력이 작은 lithium ferrite를 개발하고 물리적인 특성을 조사하기 위하여 Li0.48-0.5xBi0.02Ni0.04ZnxFe2.46-0.5xO4의 조성식을 갖는 시편을 제조하였다. ZnO을 첨가하여 변화시킴에 따라 잔류자기(Bm)가 증가하고 보자력(Hc)이 낮아졌으나 각형비 R은 감소하였다. 105$0^{\circ}C$에서 소결한 시편의 경우 R=0.82, Hc=1.8Oe로 나타났고 110$0^{\circ}C$에서 소결한 시편의 경우 R=0.75 및 Hc=1.70Oe인 값을 얻었다. Tc는 463$^{\circ}C$로 측정되었고 주변온도 변화에 대한 Br값의 변화가 매우 안정된 0.09~0.11 값으로 나타났다.