It was found that Li-Zn-Cu ferrite has remarkable temperature dependence of complex permeability which conformed to an exponential function. In order to apply the Li-Zn-Cu ferrite to the temperature sensor devices, the fundamental investigation was executed with a LC resonant circuit using Li-Zn-Cu ferrite and capacitor. Its impedance spectra greatly depended on atmosphere temperature, and such dependence was revolved by a simple approximate line of an exponential or a linear function. Consequently, the authors suggested that a micro-chip temperature sensor device will be obtained by using Li-Zn-Cu ferrite which has both superior temperature sensitivity and high-frequency performance.
