Magnetocaloric properties of rare-earth substituted DyCrO₃

Recently, there has been a focus on the need for efficient refrigeration technology without the use of expensive or harmful working fluids, especially at temperatures below 30 K. Solid state refrigeration, based on the magnetocaloric effect, provides a possible solution to this problem. The rare-earth chromites (RCrO₃), especially DyCrO₃, with its large magnetic moment dysprosium ion, are potential candidates for such an application. The Dy³⁺ ordering transition at low temperatures (<10 K) likely causes a large magnetocaloric response in this material. This study investigates the possibility of tuning the magnetocaloric properties through the use of rare-earth substitution. Both Y³⁺ and Ho³⁺ substitutions were found to decrease the magnetocaloric response by disrupting the R³⁺ ordering. Whereas Er³⁺ substitution was found to increase the magnetocaloric response, likely due to an increase in the R³⁺ ordering temperature. The large magnetocaloric entropy change of Er³⁺ substituted DyCrO₃ (10.92 J/kg K with a relative cooling power of 237 J/kg at 40 kOe and 5 K) indicates that this material system is well suited for low temperature (<30 K) solid state refrigeration applications