Investigation of the crystal structure, magnetic phase transition and magnetocaloric effect in RE5Ni2In4 (RE = Dy, Ho and Er) compounds

The structure, magnetic phase transition and magnetocaloric properties of ternary intermetallic RE5Ni2In4 (RE = Dy, Ho and Er) compounds are investigated. The results of XRD and Rietveld refinement confirm that all the samples crystallized in the orthorhombic Lu5Ni2In4-type structure belonging to the space group of Pbam. The RE5Ni2In4 compounds show various magnetic phase transition behaviors, i.e. a ferromagnetic to paramagnetic (FM-PM) phase transition at TC = 105 K together with an antiferromagnetic to ferromagnetic (AFM-FM) at low temperature TN = 20 K for the Dy5Ni2In4, the Ho5Ni2In4 reveals two different kinds of phase transitions at TN = 31 K and TC = 19 K which are corresponding to the second order PM-AFM and the first order AFM-FM phase transitions, and a PM-FM phase transition exists in the Er5Ni2In4 at TC = 21 K. In addition, a large hysteresis loop with particular shape and a high coercive field (HC = 4 T) are observed at 3 K for the Dy5Ni2In4 compound. The corresponding isothermal magnetization curves change into the state of reversibility when the temperature is 60 K, and the coercivity is reduced to zero. The maximum values of −ΔSMmax are determined to be 4.7, 10.1 and 10.2 J/kg K around TC for the RE5Ni2In4 (RE = Dy, Ho and Er) compounds in a field of 7 T, respectively.