Magnetic properties and specific heat of MPS3 (M=Mn, Fe, Zn)

Abstract The magnetic properties and specific heat of MPS 3 (M=Mn, Fe and Zn) have been investigated. While ZnPS 3 is non-magnetic, MnPS 3 and FePS 3 are antiferromagnets with the Neel temperature T N of 78 and 118 K, respectively. Nevertheless, the specific heat of MnPS 3 and FePS 3 is smaller than that of ZnPS 3 below about 20 K. The temperature dependence of the magnetic specific heat C M of MnPS 3 shows a broad hump which is characteristic to the two dimensional magnetic materials and a small sharp peak at T N . On the other hand, that of FePS 3 shows a large sharp peak at T N . As for FePS 3 , the temperature dependences of the magnetization M and C M are well reproduced by taking account of the magneto-elastic effect which introduces an additional term proportional to the square of the average value of the spin to the exchange coupling constant. As for MnPS 3 , marked two dimensional characters apear in the temperature dependence of M and C M . The observed T N is much smaller than the paramagnetic Curie temperature of 240 K obtained from the temperature dependence of the magnetic susceptibility at high temperature.