Enhancement of the magnetocaloric effect and magnetic transition temperature in LaFe11.5Al1.5 by hydrogenation

The magnetic properties and magnetocaloric effect (MCE) of LaFe11.5Al1.5Hx ( x = 0.12 , 0.6 and 1.3) have been investigated. Introducing hydrogen atoms can drive the Curie temperature T C to ambient temperature. The magnetic transition is changed from second order to weakly first order with increasing hydrogen content, leading to an increase in the magnetic entropy change Δ S M . The maximal value of Δ S M for x = 1.3 is determined to be 6.7 J/kg K at 295 K under a field change of 0–2 T. Good reversible MCE at low fields makes the hydrides promising room-temperature magnetic refrigerants.