The effects of interstitial atoms H and B on magnetic properties and magnetocaloric effect in LaFe11.5Al1.5 compound

The changes in magnetic properties of LaFe11.5Al1.5Hx and LaFe11.5Al1.5By have been investigated. By introducing interstitial atoms H or B, the magnetic ground state is changed from the antiferromagnetic to the ferromagnetic state, accompanied by significant increases in the saturated magnetization (Ms) and the Curie temperature (TC). An attractive feature is that the magnetic transition from the second-order to the weakly first-order with increasing hydrogen content compared to the magnetic transition from the weakly first-order to the second-order with increasing boron content. The maximum magnetic entropy change (−ΔSM) under a field change of 0–5 T increases from 10.1 J/kg · K for hydrogen content x = 0.12 to 12.3 J/kg · K for x = 1.3, while decreases from 9.6 J/kg · K for boron content y = 0.1 to 9.2 J/kg · K for y = 0.3