Magnetic Entropy Changes of SmMn<SUB>2</SUB>Ge<SUB>2</SUB> under High Pressure

Abstract

In order to obtain the information about magnetic states of reentrant ferromagnet, SmMn 2 Ge 2 , we have studied the pressure effect on magnetocaloric properties by magnetization measurements under high pressures up to 1.2 GPa in the temperature range from 5 to 300 K. Using the Maxwell relation, we estimated the magnetic entropy change ΔS M to be 0.65JK- 1 mol -1 at T 1 (= 100 K) and 0.53JK -1 mol -1 at T 2 (= 150 K) under 0.1 MPa. By applying pressures up to 0.5 GPa, ΔS M (T 1 ) is enhanced (2.0 JK -1 mor -1 ), while Δ SM (T 2 ) is slightly suppressed (0.4 JK -1 mol -1 ). The obtained values of |ΔS M | were discussed on the basis of a mean field theory using a two-sublattice model.