Enhancement of cutoff frequency for planar anisotropic Y₂Co₁₇ by reductive diffusion method

With the continuous development of wide-band-gap semiconductors such as silicon carbide and gallium nitride, power conversion electronic devices are required to operate at higher frequencies. Traditional magnetic materials are limited by Snoek’s limit and cannot simultaneously achieve high permeability and high cutoff frequency; however, magnetic materials with planar anisotropy can overcome Snoek’s limit. This work is devoted to the preparation of high-performance soft magnetic composite materials with high permeability, high cutoff frequency, and low losses to meet the requirements of high resonant frequency and device miniaturization. The rare-earth soft magnetic material Y₂Co₁₇ was selected and prepared by the reduction diffusion method. The effects of ball milling time and ball-to-material ratio on the crystal structure and magnetic properties of Y₂Co₁₇ were investigated to determine the optimum milling conditions that enable Y₂Co₁₇ magnetic powder to exhibit excellent shape anisotropy and significantly increase the cutoff frequency. The results show that the shape anisotropy of Y₂Co₁₇ magnetic powder is optimal when the ball milling time is 4 h and the ball-to-material ratio is 10:1, resulting in an increase in the cutoff frequency of the Y₂Co₁₇/epoxy composite to 170 MHz. This study demonstrates the promising potential of Y₂Co₁₇/epoxy composites for applications requiring high resonant frequency and device miniaturization.