When the magnetic material is used as the high frequency devices such as RF inductor and power inductor, the domain walls does not move, so a soft magnetic material with an uniaxial magnetic anisotropy is often used in the case. A magnetic field is applied in the direction of the hard axis, magnetization rotation is used in the soft magnetic material. In the soft magnetic material, not only the higher real part and the lower imaginary part of the complex permeability but also the electrical resistivity should be high. For example, when it is used for the magnetic core of an inductor, eddy current loss increases when the electric resistivity of the material is low. In addition, various resources such as reducing the eddy current loss by putting a slit in the magnetic material are required for RF devices and their applications.