Spin transitions in the Fe_xMn_1-xS₂ system

Pressure-induced spin transitions of the Fe2+ and the Mn2+ ions in the FexMn1−xS2 system are investigated using calculations based on density-functional theory within the generalized gradient approximation
GGA +U formalism. MnS2 shows a transition from a high-spin to a low-spin state at high pressure. The transition pressures decrease with increasing Fe content, and at high Fe content, transition pressures approaching zero are obtained. However, the volume change at the transition remains remarkably constant as long as both Fe and Mn participate.