Magnetocaloric effect and improved relative cooling power in (La _0.7Sr_0.3MnO₃/SrRuO₃) superlattices

Magnetic properties of a series of (La_0.7Sr _0.3MnO₃/SrRuO₃) superlattices, where the SrRuO₃ layer thickness is varying, are examined. A room-temperature magnetocaloric effect is obtained owing to the finite size effect which reduces the T_C of La_0.7Sr_0.3MnO₃ layers. While the working temperature ranges are enlarged, -ΔS_M ^max values remain similar to the values in polycrystalline La _0.7Sr_0.3MnO₃. Consequently, the relative cooling powers are significantly improved, the microscopic mechanism of which is related to the effect of the interfaces at La_0.7Sr _0.3MnO₃/SrRuO₃ and higher nanostructural disorder. This study indicates that artificial oxide superlattices/multilayers might provide an alternative pathway in searching for efficient room-temperature magnetic refrigerators for (nano) micro-scale systems.