Exchange Inversion in Mn2−xCrxSb

Abstract

Compounds of the form Mn2−xCrxSb show a first-order ferrimagnetic to antiferromagnetic phase transitionwith decreasing temperature. Sublattices composed of the three adjacent ferrimagnetically aligned (001)planes Mn(II)-Mn(I)-Mn(II) are ferromagnetically ordered above the transition temperature Ts and antiferromagnetically ordered below Ts. The exchange interaction between these sublattices changes sign at a critical interlayer distance. The discontinuous change in interlayer distance at Ts is proportional to the square of the magnetization of the sublattice in agreement with Kittel's conclusions.