Magnetic properties and magnetocaloric effect of the Cr-based spinel sulfides Co_(1-x)Cu_xCr_2S_4

Crystallographic structure, magnetic properties, and magnetic entropy change of the Cr-based spinel sulfides Co_(1-x)Cu_xCr_2S_4(x = 0–0.8) have been investigated. All these compounds crystallize into the cubic spinel structure, the Cu substitution shrinks linearly the lattice constant at a ratio of 0.0223 per Cu atom in the unit cell, and enhances linearly the Curie temperature and the spontaneous magnetization at the rates of 18K and 0.33 μB/f.u. per Cu atom in the unit cell,respectively. All these compounds show a typical behavior of second order magnetic transition, and a room temperature magnetic entropy change of 2.57 J/kg·K is achieved for Co_(0.4)Cu_(0.6)Cr_2S_4.