Realization of magnetostructural coupling in a high temperature region in Mn0.85Co0.3Ni0.85Si1-xGax system

First-order magnetostructural transition between ferromagnetic orthorhombic and paramagnetic hexagonal phases has been widely investigated in substituted MnNiSi-based alloys. However, due to the large substitution level, the Curie temperature of the orthorhombic phase decreases remarkably, leading to a shrunken or closed temperature interval in which the magnetostructural transition between paramagnetic hexagonal and ferromagnetic orthorhombic phases can take place. In this paper, a three-site co-substitution system, Mn0.85Co0.3Ni0.85Si1-xGax, was reported. In this system, the structural transformation temperature can be efficiently reduced with a low level of substitution. Based on this improvement, the Curie temperature of the orthorhombic phase maintains at a high value. The magnetostructural transition can be established in a temperature interval of 303 K. The upper limit of this temperature interval is as high as 542 K, which is the highest among the MnM'X-based compounds.