Magnetic phase transition and cryogenic magnetocaloric properties in the <i>RE</i>6Ni2.3In0.7 (<i>RE </i>= Ho, Er, and Tm) compounds

The magnetocaloric (MC) properties in many rare-earth (RE)-containing magnetic solids have been intensively investigated, which are aimed to develop suitable candidates for cryogenic magnetic cooling applications and to better understand their intrinsic magnetic characters. We herein fabricated the RE-rich RE6Ni2.3In0.7 (RE = Ho, Er, and Tm) compounds and investigated their structural, magnetic, and MC properties by experimental determination and theoretical calculations. All of these RE6Ni2.3In0.7 compounds crystallize in an Ho6Co2Ga-type structure with an orthogonal Immm space group and order magnetically around the temperatures of 10.6 and 33.0 K for Ho6Ni2.3In0.7, 11.0 K for Er6Ni2.3In0.7, and 7.6 K for Tm6Ni2.3In0.7, respectively. Large cryogenic reversible MC effects were observed in these RE6Ni2.3In0.7 compounds. Moreover, their MC parameters of maximum magnetic entropy changes, relative cooling powers, and temperature-averaged magnetic entropy change are comparable with those of some recently updated cryogenic MC materials.