Date:

2025-04-30

Title of Paper:

Temperature invariable magnetization in Co-Al-Fe alloys by a martensitic transformation

Journal:

Applied Physics Letters

Summary:

Recently, it has been reported in a dual-phase ferromagnetic Fe-Ga alloy, highly thermally stable magnetization is achieved by a diffusional transformation between the two phases with different magnetizations, which compensates for the inevitable magnetization reduction. Contrasting with the compensation mechanism through a diffusional transformation, here we report a diffusionless martensitic transition can also be used as a compensation mechanism for achieving nearly temperature invariable magnetization. We found that ferromagnetic Co-Al-Fe alloys with a non-thermoelastic martensitic transformation exhibit almost unchanged magnetization up to 830 K (about 81% TC). In-situ heating transmission electron microscopy (TEM) reveals that the gradual transformation from a hexagonal close-packed (hcp) martensite phase with lower magnetization into a face-centered-cubic (fcc) parent phase with higher magnetization occurs over a wide temperature range, giving rise to such temperature invariable magnetization. The electrical resistivity measurement reveals that the fcc → hcp transformation can be repeated during heating-cooling cycles, which can be used to design temperature invariable magnets with long cycling life.

Co-author:

F. Ye, T.Y. Ma*, S. Ren, A.D. Xiao, X.L. Liu, Y.C. Ji*, and X.B. Ren*

Volume:

113

Page Number:

172402

Translation or Not:

No

Date of Publication:

2018-10-22