Observation of giant magnetocaloric effect under low magnetic field in Eu_1−xBa_xTiO₃

The magnetic properties and magnetocaloric effect in Eu_1−xBa_xTiO₃(x = 0, 0.04, 0.08, 0.1) compounds are investigated. With slight Ba-doping, the antiferromagnetic ordering of pure EuTiO₃can be significantly changed to ferromagnetic due to the size Ba²⁺ion bigger than Eu²⁺. A giant reversible magnetocaloric effect and large RC in Eu_1−xBa_xTiO₃compounds were observed. The maximum value of magnetic entropy change (−ΔS_M^max) reaches to 41.4 J/kg K for Eu_0.92Ba_0.08TiO₃under the magnetic field change of 5 T. Especially, under the magnetic field changes of 1 and 2 T, the values of −ΔS_M^maxare evaluated to be 12.5 and 23.4 J/kg K and the maximum values of RC are 54 and 119 J/kg, without magnetic and thermal hysteresis for Eu_0.92Ba_0.08TiO₃. Therefore, the giant reversible magnetocaloric effect and large RC make the Eu_1−xBa_xTiO₃compounds could be considered as a good candidate material for low-temperature and low-field magnetic refrigerant.