Intrinsic magnetocaloric effect at a first-order magnetic transition

Shenyang National Laboratory for Materials Science, Institute of Metal Research, and International Center for Materials Physics, Chinese Academy of Sciences - Shenyang 110016, PRC

^a wjren@imr.ac.cn

Received: 9 March 2011
Accepted: 24 January 2012

Abstract

A four-parameter method has been developed to determine the magnetocaloric effect associated with a first-order magnetic transition. In order to prevent misevaluation due to the intrinsically irreversible features, the transition is mimicked by a reversible process. The magnetization and the isothermal magnetic-entropy change are shown to be dependent on only four intrinsic parameters, which can be easily obtained in experiments. A new method to calculate the magnetic-entropy change is derived, which is referred to as Landau approach. The four-parameter method as well as the Landau approach are demonstrated on the famous magnetocaloric material LaFe_11.5Si_1.5. They benefit from the experimental investigation of MCE very much and make the characterization of MCE much easier. This may be helpful for the search of better magnetocaloric materials.