Structural and cryogenic magnetic properties of RE2Ni2In (RE = Pr, Nd, Dy and Ho) compounds.

The crystal structures, magnetic properties and magneto-caloric effects (MCEs) of RE2Ni2In (RE = Pr, Nd, Dy and Ho) compounds were investigated. The results indicate that Pr2Ni2In and Nd2Ni2In compounds have a tetragonal Mo2FeB2-type structure belonging to the P4/mbm space group and undergo a second-order paramagnetic to ferromagnetic (PM to FM) transition at a Curie temperature (TC) of 7.5 and 10.5 K, respectively, whereas Dy2Ni2In and Ho2Ni2In compounds have an orthorhombic Mn2AlB2-type structure belonging to the space group Cmmm and possess a magnetic transition from PM to antiferromagnetic (AFM) at a Néel temperature TN of 19 and 10.5 K together with a first-order field induced metamagnetic transition, respectively. Moreover, an additional magnetic transition at a lower temperature of around 5.5 K is detected for the Ho2Ni2In compound. A considerable reversible magneto-caloric effect is observed accompanying the magnetic phase transition, and the maximum values of the magnetic entropy change (-ΔS) of the present RE2Ni2In series compounds are determined to be 9.3, 11.5, 6.4 and 11.5 J kg-1 K-1 with a magnetic field change (ΔH) of up to 0-5 T for RE = Pr, Nd, Dy and Ho, respectively.