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

Abstract We studied the magnetism and crystal structure of Fe 1 - x Mn x Cr 2 O 4 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 Mn 2 + for Fe 2 + , because a Mn 2 + ion in the high-spin state ( e 2 t 3 ) 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.