Date of this Version
JOURNAL OF APPLIED PHYSICS 118, 033905 (2015)
Mn54-xAl43C3Zrx (x=1, 3) alloys were prepared by rapid solidification followed by heat treatment to produce the ferromagnetic s phase. The substitution of Zr for Mn in the structure resulted in an increase of the saturation magnetization (Ms) compared to that of Mn54-xAl43C3. While the highest Ms (12861 emu/g) was obtained in Mn54-xAl43C3Zr1, the coercivity was also improved to 1.62 kOe, compared to 1.25 kOe for Mn54-xAl43C3. To further improve the coercivity through grain refinement, additional C (1%, 3%, 5%, and 7%) was added to Mn54-xAl43C3Zr1. An increase in the coercivity was observed due to a decrease of grain size and the formation of nonmagnetic phases, which reduced the magnetostatic interactions between the s-phase grains. However, excess C reduced the saturation magnetization due to the formation of the other non-ferromagnetic phases, including e, c2, and b phases.