Effect of Mn-substitution on magnetic and structural properties in FeCr2O4

We studied the magnetism and crystal structure of Fe1-xMnxCr2O4 solid solutions to explore the interplay between the orbital and spin degrees of freedom in the spinel oxide system. Cooperative Jahn-Teller transition temperature decreases with partial substitution of Mn2+ for Fe2+, because a Mn2+ ion in the high-spin state (e2t3) has no orbital degree of freedom. In the partially substituted compounds, the ferrimagnetic transition induces the second structural transition from tetragonal to orthorhombic system, which might be explained by a possible competition between the single-cluster Jahn-Teller distortion and spin-orbit coupling