Strong Magnetocaloric Coupling in Oxyorthosilicate with Dense Gd 3+ Spins.

Searching for working refrigerant materials is the key element in the design of magnetic cooling devices. Herein, we report on the thermodynamic and magnetocaloric parameters of an X 1 phase oxyorthosilicate, Gd 2 SiO 5 , by field-dependent static magnetization and specific heat measurements. An overall correlation strength of | J | S 2 ≈ 3.4 K is derived via the mean-field estimate, with antiferromagnetic correlations between the ferromagnetically coupled Gd-Gd layers. The magnetic entropy change -Δ S m is quite impressive, reaches 0.40 J K -1 cm -3 (58.5 J K -1 kg -1 ) at T = 2.7 K, with the largest adiabatic temperature change T ad = 23.2 K for a field change of 8.9 T. At T = 20 K, the lattice entropy S L is small enough compared to the magnetic entropy S m , S m / S L = 21.3, which warrants its potential in 2 -20 K cryocoolers with both the Stirling and Carnot cycles. Though with relatively large exchange interactions, the layered A-type spin arrangement ultimately enhances the magnetocaloric coupling, raising the possibilities of designing magnetic refrigerants with a high ratio of cooling capacity to volume.