Synthesis, structural, and magnetic properties of Heusler-type Mn2-xFe1+xGe (0.0 ≤ x ≤ 1.0) alloys

Abstract

Bulk Mn2-xFe1+xGe (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 Mn2FeGe alloy was also produced in ribbon form by rapid solidification. A study of the structural and magnetic properties is presented. Contrary to theoretical predictions, Mn2FeGe crystallizes in a hexagonal DO19 crystal structure (space group P63/mmc) and orders ferromagnetically with a saturation magnetization (MS) value of ~1.7 µB/f.u. in the ground state. With the substitution of Fe for Mn in bulk Mn2-xFe1+xGe, we observed an increase in the FM interactions with a maximum MS value of 5.1 µB/f.u. for x = 1.0, and a significant progressive increase in the Curie temperature (TC) in a wide range spanning ~200 K to over 400 K.