Pressure effects on the magnetic transition temperatures of NiS2

Both antiferromagnetic (TN) and weak ferromagnetic (Tc) transition temperatures of NiS2 have been measured under pressure up to 18.4 kbar. Values of dTN/dP=(0.9 ± 0.1) deg/kbar and dTc/dP=(0.4 ± 0.1) deg/kbar are obtained. The present results allow estimates of the magnetic Gruneisen constant γm = - d ln TN/d ln V of (26±5) and of the entropy change of (1.4±0.5) J/mol·deg at the first order transition temperature Tc.