Structural and magnetic properties of Sb substituted LTP Mn-Bi annealed ribbons

Abstract

We optimized the composition of Mn-Bi alloy, examined the effects of third element substitution of Sn, Cu, Al, and Sb on the magnetic properties, and investigated the microstructures and magnetic properties of Sb substituted Mn-Bi annealed ribbons. The optimized composition was Mn54Bi46, and it was found that the Sb substitution had the most positive effects on the magnetic properties among the substitution elements. Thus, we accomplished a detailed investigation on Mn54Bi46-xSbx (0.0 ≤ x ≤ 5.0) annealed ribbons. The fracture planes of the annealed ribbons revealed that the grain size drastically decreased from a few tens of microns to submicrons close to the single domain size, which substantially enhanced the coercivity (Hc), remanent magnetization (Mr), and maximum energy product ((BH)max). As a result, as the Sb content changed from 0 to 1.5, the Mr, Hc, and (BH)max of randomly oriented samples increased significantly from 14.7 emu/g, 0.50 kOe, and 0.15 MGOe to 37.2 emu/g, 8.15 kOe, and 3.27 MGOe, respectively. Furthermore, the temperature dependence of Hc on the Sb substitution showed significant enhancement over a wide temperature range from 223 to 378 K, suggesting that Mn-Bi alloy can be used in electrical vehicles. © 2023 The Author(s)