抄録
In order to obtain the information about nonlinear terms of the high frequency magnetic susceptibility at 2MHz near the Curie temperature the 2nd and 3rd order nonlinear terms against the high frequency magnetic field are derived from the observations of the 2nd and 3rd harmonics. Both terms decrease abruptly as the temperature deviates from the Curie temperature. It is a very remarkable result that the 2nd harmonic signal is observed above the Curie temperature in contradiction to the simple theoretical consideration. As for the 3rd harmonic its temperature dependence is explained qualitatively by the molecular field theory.