Observation of giant magnetocaloric effect under low magnetic fields in EuTi_1-xCo_xO₃

The magnetic properties and magnetocaloric effect (MCE) in EuTi_1-xCo_xO₃ (x=0, 0.025, 0.05, 0.075, 0.1) compounds have been investigated. When the Ti⁴⁺ ions were substituted by Co²⁺ ions, the delicate balance was changed between antiferromagnetic (AFM) and ferromagnetic (FM) phases in the EuTiO₃ compound. In EuTi_1-xCo_xO₃ system, a giant reversible MCE and large refrigerant capacity (RC) were observed without hysteresis. The values of-△ S_M^max were evaluated to be around 10 J·kg^-1·K^-1 for EuTi_0.95Co_0.05O₃ under a magnetic field change of 10 kOe. The giant reversible MCE and large RC suggests that EuTi_1-xCo_xO₃ series could be considered as good candidate materials for low-temperature and low-field magnetic refrigerant.