Tuned bi-anisotropy of Y2Co14B nanocrystalline magnetic alloys toward high-frequency applications

The prevalence of wide-bandgap semiconductors urges the development of advanced soft magnetic materials for high-frequency applications. While soft magnetic alloys are limited by resonances at elevated frequencies, the incorporation of planar anisotropy serves as an effective strategy to overcome this dilemma and extend their potential for high-frequency applications. Herein, nanocrystalline Y₂Co₁₄B alloys have been designed with tuned magnetocrystalline and shape bi-anisotropy via melt spinning and magnetic field-assisted annealing. With the application of zero, transverse, rotational and longitudinal magnetic fields (denoted as ZFA, TFA, RFA and LFA), the effects of field direction and annealing time on microstructural and performance evolution have been investigated. Compared with ZFA, magnetic field-assisted annealing not only promotes the growth of nanograins but also alters the coincidence degree between intrinsic easy-plane (IEP) and artificial easy-plane (AEP) structures. While the random distribution of IEP structure is achieved for the RFA due to the formation of non-orientated nanograins, directional magnetic field-assisted annealing contributes to preferentially orientated (006) nanograins, especially for the LFA, resulting in optimal coincidence between the magnetocrystalline anisotropy and shape anisotropy. Such enhancement facilitates the transformation of magnetic domain structures into in-plane configurations with strip-like features. Consequently, a large ratio between the out-of-plane and in-plane anisotropy (H_out/H_in) and improved softness of the alloy can be achieved, providing valuable references for future fabrication of rare-earth (R) transition-metal (T) alloys with superior easy-plane characteristics.