Cryogenic magnetic and magnetocaloric properties in anhydrous rare-earth sulfate RE2(SO4)3 (RE = Tb, Dy, Ho, Er)

Abstract

The cryogenic magnetocaloric (MC) properties in various types rare-earths (RE)-based magnetic materials have recently been investigated to identify suitable candidate materials for active magnetic cooling applications and better understanding their intrinsic properties. Herein, we obtained four anhydrous RE-based sulfates, namely the RE₂(SO₄)₃ (RE = Tb, Dy, Ho, Er), through a thermal decomposition method and analyzed their cryogenic magnetic and MC properties. All of the present sulfates possess an orthorhombic-type structure with space group of Pbcn and show no distinct magnetic ordering above 2 K. Large cryogenic MC effects and remarkable performances were realized. Under magnetic field variations of 0–70 kOe, the deduced MC parameters of magnetic entropy changes, relative cooling powers, and temperature-averaged entropy changes (lift-temperature of 5 K) values are as follows: 11.4J/kgK, 257.5J/kg, and 11.2J/kgK for Tb₂(SO₄)₃; 18.6J/kgK, 232.0J/kg, and 17.5J/kgK for Dy₂(SO₄)₃; 14.8J/kgK, 316.4J/kg, and 14.5J/kgK for Ho₂(SO₄)₃; 14.4J/kgK, 254.9J/kg, and 13.2J/kgK for Er₂(SO₄)₃, respectively. These deduced MC values of the present RE₂(SO₄)₃ are at a similarly high level as those of most recently updated RE-based MC materials with notable cryogenic performances, making them may considerable for active cooling applications.