Large reversible magnetocaloric effect induced by metamagnetic transition in antiferromagnetic HoNiGa compound

【摘要】 The magnetic properties and magnetocaloric effects（MCE） of Ho Ni Ga compound are investigated systematically.The Ho Ni Ga exhibits a weak antiferromagnetic（AFM） ground state below the Neel temperature TNof 10 K, and the AFM ordering could be converted into ferromagnetic（FM） ordering by external magnetic field. Moreover, the field-induced FM phase exhibits a high saturation magnetic moment and a large change of magnetization around the transition temperature,which then result in a large MCE. A large-?S_M of 22.0 J/kg K and a high RC value of 279 J/kg without magnetic hysteresis are obtained for a magnetic field change of 5 T, which are comparable to or even larger than those of some other magnetic refrigerant materials in the same temperature range. Besides, the μ₀H^2/3dependence of |?S_M^pk| well follows the linear fitting according to the mean-field approximation, suggesting the nature of second-order FM–PM magnetic transition under high magnetic fields. The large reversible MCE induced by metamagnetic transition suggests that Ho Ni Ga compound could be a promising material for magnetic refrigeration in low temperature range.更多还原

【Abstract】 The magnetic properties and magnetocaloric effects（MCE） of Ho Ni Ga compound are investigated systematically.The Ho Ni Ga exhibits a weak antiferromagnetic（AFM） ground state below the Neel temperature TNof 10 K, and the AFM ordering could be converted into ferromagnetic（FM） ordering by external magnetic field. Moreover, the field-induced FM phase exhibits a high saturation magnetic moment and a large change of magnetization around the transition temperature,which then result in a large MCE. A large-?S_M of 22.0 J/kg K and a high RC value of 279 J/kg without magnetic hysteresis are obtained for a magnetic field change of 5 T, which are comparable to or even larger than those of some other magnetic refrigerant materials in the same temperature range. Besides, the μ₀H^2/3dependence of |?S_M^pk| well follows the linear fitting according to the mean-field approximation, suggesting the nature of second-order FM–PM magnetic transition under high magnetic fields. The large reversible MCE induced by metamagnetic transition suggests that Ho Ni Ga compound could be a promising material for magnetic refrigeration in low temperature range.更多还原