Giant Low-Field Magnetocaloric Effect in the Superlattice Antiferromagnetic ErFe<sub>2</sub>Si<sub>2</sub> Compound
Dingxin Wang, Xinqi Zheng, Jiawang Xu, Lunhua He, Yajing Gao, He Huang, Hui Wu, Xueqian Cao, Dan Liu, Jianxin Shen, Guijie Wang, Jingyan Zhang, Yanfei Wu, Fengxia Hu, Shouguo Wang, Baogen Shen
Abstract
We present herein a systematic study of a polycrystalline magnetocaloric compound ErFe 2 Si 2 . It exhibits a transition from the antiferromagnetic to the paramagnetic phase around 3.0 K according to magnetic and heat capacity measurements. Neutron powder diffraction revealed that ErFe 2 Si 2 possesses a superlattice magnetic structure with a propagation vector of (0, 0, 0.5). The superlattice magnetic structure can be modeled by a transverse spin density wave (cosine-modulated) or a spiral type, which cannot be distinguished solely by neutron powder diffraction (NPD) pattern fitting. The stability of different types of magnetic structures was also investigated by first-principles calculations. The ErFe 2 Si 2 compound shows a giant magnetocaloric effect with a maximal negative magnetic entropy change and an adiabatic temperature change of 11.5 J/kg K and 5.7 K, respectively, under the field change of 0–1 T. The large low-field magnetocaloric effect is related to its low critical field of metamagnetic transition and its low quasi-saturation magnetic field. The excellent performance of ErFe 2 Si 2 makes this compound a potential magnetocaloric material for applications at liquid helium temperatures.