Magnetocaloric effect and improved relative cooling power in (La <inf>0.7</inf>Sr<inf>0.3</inf>MnO<inf>3</inf>/SrRuO<inf>3</inf>) superlattices

Magnetic properties of a series of (La0.7Sr 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 TC of La0.7Sr0.3MnO3 layers. While the working temperature ranges are enlarged, -ΔSMmax values remain similar to the values in polycrystalline La 0.7Sr0.3MnO3. Consequently, the relative cooling powers are significantly improved, the microscopic mechanism of which is related to the effect of the interfaces at La0.7Sr 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. © 2011 IOP Publishing Ltd Printed in the UK & the USA.