Impact of strain on the magnetocaloric effect of oxide heterostructures.

We report a detailed study of the magnetocaloric effect in heterostructures of La 2 NiMnO 6 and La 2/3 Sr 1/3 MnO 3. The shape, width and magnitude of the temperature dependence of the magnetic entropy change (Δ S m ) for these multilayer samples are affected by their layout with a clear impact from epitaxial strains on each layer. A large Δ S m over a wide temperature range which goes beyond room temperature is observed in all samples. We observe a temperature-independent table-top-like Δ S m over a temperature range as large as 100 K in the trilayer samples. La 2 NiMnO 6 double perovskite with multiple magnetic phase transitions sensitive to strain is the key to tuning and shaping the temperature dependence of the magnetic entropy changes to suit the requirements of several cooling cycles. • Epitaxial bilayer and trilayer samples of La 2 NiMnO 6 and La 2/3 Sr 1/3 MnO 3 were grown using pulsed laser deposition technique. • Structural and magnetic measurements have been performed to characterize the samples. • A large and almost temperature independent magnetocaloric effect was obtained extending from 175K up to above room temperature in the heterostructures. • Magnetic and magnetocaloric properties of the heterostructures were easily tuned and controlled by changing their layouts originating from the sensitivity of cationic ordering to strain in La 2 NiMnO 6. [ABSTRACT FROM AUTHOR]