Gd₅(Si,Ge)₄ thin film displaying large magnetocaloric and strain effects due to magnetostructural transition

Magnetic refrigeration based on the magnetocaloric effect is one of the best alternatives to compete with vapor-compression technology. Despite being already in its technology transfer stage, there is still room for optimization, namely, on the magnetic responses of the magnetocaloric material. In parallel, the demand for different magnetostrictive materials has been greatly enhanced due to the wide and innovative range of technologies that emerged in the last years (from structural evaluation to straintronics fields). In particular, the Gd₅(Si_xGe_1-x)₄ compounds are a family of well-known alloys that present both giant magnetocaloric and colossal magnetostriction effects. Despite their remarkable properties, very few reports have been dedicated to the nanostructuring of these materials: here, we report a ∼800 nm Gd₅Si_2.7Ge_1.3 thin film. The magnetic and structural investigation revealed that the film undergoes a first order magnetostructural transition and as a consequence exhibits large magnetocaloric effect (-ΔS_mMAX ∼ 8.83 J kg^-1 K^-1, ΔH = 5T) and giant thermal expansion (12000 p.p.m). The thin film presents a broader magnetic response in comparison with the bulk compound, which results in a beneficial magnetic hysteresis reduction. The ΔS_mMAX exhibited by the Gd₅(Si,Ge)₄ thin film makes it a promising candidate for micro/nano magnetic refrigeration area.