Magnetic properties and magnetocaloric effect in compound PrFe₁₂B₆

Magnetic properties and magnetocaloric effect of compound PrFe₁₂B₆ are investigated. The coexistence of hard phase PrFe₁₂B₆ and soft phase \alpha--Fe causes interesting phenomena on the curves for the temperature dependence of magnetization. PrFe₁₂B₆ experiences a first order phase transition at the Curie temperature 200 K, accompanied by an obvious lattice contraction, which in turn results in a large magnetic entropy change. The Maxwell relation fails to give the correct information about magnetic entropy change due to the first order phase transition nature. The large magnetic entropy changes of PrFe_12.3B_4.7 obtained from heat capacity method are 11.7 and 16.2 J/kg.K for magnetic field changes of 0--2 T and 0--5 T respectively.