Application of Degree of Magnetic Freedoms and Magnetic Phase Transition in Solid State to Refrigeration

Abstract

Magnetic entropy is basically connected to freedom of magnetic moments or spins, and the discontinuity between the magnetically ordered and disordered states due to the first-order transition brings about large caloric changes. Meanwhile, the first-order transition in a real condition occurs within finite time, therefore, the transition rate is characterized by its kinetics. Especially, kinetics of the magnetic transition is affected by the magnetic dipole interaction. We discuss these issues with referring the data of La(Fe_xSi_1-x)₁₃ itinerant metamagnetic compounds.