Synthesis, structural, and magnetic properties of Heusler-type Mn_(2-x)Fe_(1+x)Ge (0.0 ≤ x ≤ 1.0) alloys

摘要

Bulk Mn_(2-x)Fe_(1+x)Ge (0.0 ≤ x ≤ 1.0) alloys have been synthesized by arc-melting followed by a low temperature homogenization thermal annealing, whereas for comparison purposes the Mn_2FeGe alloy was also produced in ribbon form by rapid solidification. A study of the structural and magnetic properties is presented. Contrary to theoretical predictions, Mn_2FeGe crystallizes in a hexagonal DO_(19) crystal structure (space group P63/mmc) and orders ferromagnetically with a saturation magnetization (M_S) value of ～1.7 μ_B/f.u. in the ground state. With the substitution of Fe for Mn in bulk Mn_(2-x)Fe_(1+x)Ge, we observed an increase in the FM interactions with a maximum M_S value of 5.1 μ_B/f.u. for x = 1.0, and a significant progressive increase in the Curie temperature (T_C) in a wide range spanning ～200 K to over 400 K.