Pressure effect on the Curie point of the Heusler alloys Ni2MnSn and Ni2MnSb

Abstract

The pressure effect on the Curie point of the Heusler alloys Ni2MnSn and Ni2MnSb was measured. The pressure coefficients of the Curie point were determined to be (1/Tc) (dTc/dp) = 1.6×10−3 1/kbar for Ni2MnSn and 9×10−3 1/kbar for Ni2MnSb, respectively. The volume exchange striction of Ni2MnSn was also studied. The pressure coefficient of the Curie point estimated from the result of exchange striction was found to be 1.4×10−3 1/kbar, which is in good agreement with that by the direct measurement. The results are discussed on the basis of the molecular field theory taking account of the strain dependence of the exchange interaction and the Castellitz’s interaction curve.