Thermodynamics of a Magnetic Transition in MnS 2 at High Pressures

The behavior of the specific heat of MnS2 at high pressures has been studied. A significant increase in the transition temperature TN to an antiferromagnetic state with the pressure from 48.2 K at atmospheric pressure to 76 K at a pressure of 5.3 GPa has been revealed. The initial pressure derivative is dT N /dP = 4.83 K/GPa. It has been found that the parameter α = d(logT N )/d(logV ) = −6.6 ± 0.1 is significantly different from the value α = −10/3 ≈ −3.3 (Bloch relation), which is typical of numerous antiferromagnetic insulators—transition- metal oxides and fluorides. The volume jump at the magnetic transition point has been estimated. The necessity of direct dilatometric measurements of the volume has been justified.