On the derivation of the magnetocaloric properties in ferrimagnetic spinel Mn3O4

Large magnetocaloric effect has been observed in Mn3O4 around its ferrimagnetic transition at T-N = 42.75 K. Field-induced isothermal entropy changes (Delta S) were derived from both magnetic and calorimetric techniques. The maximum vertical bar Delta S vertical bar and adiabatic temperature change (Delta T-ad) at T-N are 11 J kg(-1) K-1 and 1.9 K, respectively, for a magnetic field change of 20 kOe. Moreover, it is found that the complex magnetic phase transitions taking place below T-N produce additional-but smaller-features on Delta S(T). (C) 2011 American Institute of Physics. [doi:10.1063/1.3549706]