Magnetic Properties and Magnetocaloric E ff ect in Gd 100x Co x Thin Films

We investigated the magnetic and magnetocaloric properties of Gd100-xCox (x = 40 to 56) thin films fabricated by the sputtering technique. Under an applied field change ∆H = 20 kOe , the magnetic entropy change (∆Sm) decreases from 2.64 Jkg−1K−1 for x = 44 to about 1.27 Jkg−1K−1 for x = 56. Increasing the Co concentration from x = 40 to 56 shifts the Curie temperature of Gd100-xCox (x = 40 to 56) thin films from 180 K toward 337 K. Moreover, we extracted the values of critical parameters Tc, β, γ, and δ by using the modified Arrott plot methods. The results indicate the presence of a long-range ferromagnetic order. More importantly, we showed that the relative cooling power (RCP), which is a key parameter in magnetic refrigeration applications, is strongly enhanced by changing the Co concentration in the Gd100-xCox thin films. Our findings help pave the way toward the enhancement of the magnetocaloric effect in magnetic thin films.