  A systematic investigation about the structure and magnetism of Fe75-xCr25Gax
(11<x<33) and Fe50Cr50-yGay (0<y<33) series has been carried out in this work.
It shows that the parent Fe50Cr25Ga25 phase has higher tolerance for Ga
replacing Cr than replacing Fe atoms. An abrupt flip of Curie temperature and
magnetization in the Fe50Cr50-yGay (0<y<33) series was observed at the
composition of Fe50Cr25Ga25. We proposed an explanation concerning anti-sites
occupation and magnetic structure transition in this series. The induced
structure is proved energetically favorable from first-principles calculations.
This work can help us to understand the dependences between the crystal
structure and magnetism in Fe-based Heusler compounds, and provides a method to
deduce the atomic configurations based on the evolution of magnetism.
