Magnetic properties and magnetocaloric effects of Tm _{1– x} Er _x CuAl ( x = 0.25, 0.5, and 0.75) compounds

We investigate the structural, magnetic, and magnetocaloric effects (MCE) of Tm _{1− x} Er _x CuAl ( x = 0.25, 0.5, and 0.75) compounds. The compounds undergo a second-order phase transition originating from the ferromagnetic to paramagnetic transition around 3.2 K, 5 K, and 6 K, respectively. The maximum magnetic entropy changes ( $-\mathrm{\Delta }{S}_{\mathrm{M}}^{\max }$ ) of Tm _{1− x} Er _x CuAl ( x = 0.25, 0.5, and 0.75) are 17.1 J⋅kg ⁻¹⋅K ⁻¹, 18.1 J⋅kg ⁻¹⋅K ⁻¹, and 17.5 J⋅kg ⁻¹⋅K ⁻¹ under the magnetic field in the range of 0–2 T, with the corresponding refrigerant capacity ( RC) values of 131 J⋅kg ⁻¹, 136 J⋅kg ⁻¹, and 126 J⋅kg ⁻¹, respectively. The increase of $-\mathrm{\Delta }{S}_{\mathrm{M}}^{\max }$ for Tm _0.5Er _0.5CuAl may be relevant to the change of magnetic moment distribution of Er and stress coming from element substitution. This work provides several compounds that can enrich the family of giant MCE materials in the cryogenic region.