Experimental Study of the Magnetocaloric Effect in Ni(en)(H₂O)₄SO₄·2H₂O - An S = 1 Molecular Magnet with Easy-Plane Anisotropy

Magnetocaloric properties of Ni(en)(H₂O)₄SO₄·2H₂O powder were investigated in temperature range from 2 K to 30 K in magnetic fields up to 7 T using isothermal magnetization measurements. The maximum value of the isothermal entropy change in the field 7 T is about 8 J/(kg K), with a refrigerant capacity of 55 J/kg. Temperature dependence of the isothermal entropy change under different magnetic fields is in good agreement with theoretical predictions from crystal electric field parameters.