Magnetic entropy changes of SmMn₂Ge₂ under high pressure

In order to obtain the information about magnetic states of reentrant ferromagnet, SmMn₂Ge₂, 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 0.65 JK^-1mol^-1 at T₁ (= 100K) and 0.53 JK ^-1mol^-1 at T₂ (= 150K) under 0.1 MPa. By applying pressures up to 0.5 GPa, |ΔS_M(T₁)| is enhanced (2.0 JK^-1 mol^-1), while |ΔS _M(T₂)| 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.