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=0.12x=0.12, 0.6 and 1.3) have been investigated. Introducing hydrogen atoms can drive the Curie temperature TCTC 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 ΔSMΔSM. The maximal value of ΔSMΔSM for x=1.3x=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.

Research highlights
► Introducing hydrogen atoms to LaFe11.5Al1.5Hx (x=0.12x=0.12, 0.6 and 1.3) compound can drive the Curie temperature TCTC 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 ΔSMΔSM.
► The maximal value of ΔSMΔSM for x=1.3x=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.