Exchange Inversion in Mn2−xCrxSb

Abstract

Compounds of the form ${\mathrm{Mn}}_{\text{2−x}}{\mathrm{Cr}}_x\mathrm{Sb}$ show a first-order ferrimagnetic to antiferromagnetic phase transition with 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 $T_s$ and antiferromagnetically ordered below $T_s$ . The exchange interaction between these sublattices changes sign at a critical interlayer distance. The discontinuous change in interlayer distance at $T_s$ is proportional to the square of the magnetization of the sublattice in agreement with Kittel's conclusions.