Crystal growth and magnetocaloric properties of Gd_1-xYb_xCl₃·6H₂O

Adiabatic Demagnetization Refrigeration (ADR) based on magnetocaloric effect (MCE), as an effective technology for achieving ultra-low temperature refrigeration, has attracted increasing attention. In this work, Gd_{1- x} Yb _x Cl₃·6H₂O ( x = 0, 0.06, 0.33, 0.77 and 1.00) crystals have been grown by natural evaporation method or slow cooling method. Their crystal structures and magnetic properties have been systematically investigated. The magnetic ordering temperatures ( T ₀) of the Gd_{1- x} Yb _x Cl₃·6H₂O crystals are all lower than 2 K. With increasing Yb content, the saturated magnetic moment of the materials gradually declines, accompanied by an obvious reduction in the corresponding MCE. Under a magnetic field change of 0–7 T, the maximum magnetic entropy changes reach 43.3, 39.5, 32.1, 15.5, and 11.7 J kg⁻¹ K⁻¹ for Gd_{1- x} Yb _x Cl₃·6H₂O ( x = 0, 0.06, 0.33, 0.77 and 1.00) crystals, respectively. The refrigeration capacities are 255.3, 240.9, 197.8, 88.6, and 48.6 J kg⁻¹, respectively. For a better assessing the magnetocaloric performance of Gd_{1- x} Yb _x Cl₃·6H₂O, we have also calculated the temperature averaged entropy change and relative cooling power. Our experimental results can provide valuable references for the application and development of Gd_{1- x} Yb _x Cl₃·6H₂O as low-temperature magnetic refrigerant.