A spin-calorics device based on La0.7Sr0.3MnO3/SrRuO3 superlattices

Abstract

High quality La0.7Sr0.3MnO3/SrRuO3 superlattices with ultrathin individual layers were grown by pulsed laser deposition and were studied by magnetometry and magnetoresistance measurements. Depending on layer thickness and structural quality, exchange biasing could be observed both in magnetization and magnetotransport. In this regime the superlattice magnetization forms an exchange spring that leads to a reversible field dependence of the magnetoresistance and the magnetic work. It is shown that the magnetic work and the magnetocaloric effect can be tuned by the SrRuO3 layer thickness. This opens up the possibility of fabricating spin-caloric devices from wedge-shaped superlattices with self-sustaining Seebeck effect. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) In this Letter a spin-caloric device is proposed that consists of a wedge-shaped La0.7Sr0.3MnO3/SrRuO3 superlattice (SL). Studies of SLs with various layer thicknesses show that the magnetic work can be strongly influenced by the engineering of the crystalline symmetry or the use of exchange biasing. A SL wedge in a rapidly varying magnetic field should therefore support a self-sustained Seebeck effect. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.