Thermal property of magnetic materials for hydrogen magnetic refrigeration and effect of magnetic field on them

It is well know that some of rare earth compounds that show giant magnetocaloric effect are utilized for adiabatic magnetic refrigeration (ADR) at cryogenic temperatures. Recent development of materials science, however, suggested practical possibility of magnetic refrigeration at higher temperatures using Active Magnetic Regenerative Refrigeration (AMRR). A project WE-NET plans to make use of AMRR to liquefy hydrogen from room temperature in hydrogen plants for upcoming hydrogen energy society. Higher efficient liquefaction requires magnetic materials with higher magnetocaloric effect, higher thermal conductivity and lower thermal expansion. This paper surveys thermal properties of some of promising rare earth compounds and its magnetic dependence for deep insight in its nature as well as for contribution to a database for designing and development of the practical AMRR for hydrogen liquefaction.