Tunable magnetocaloric effect and enhanced refrigerant capacity in composite-like oxide heterostructures

We report a detailed study of the magnetocaloric effect in heterostructures of La2NiMnO6 and La2/3Sr1/3MnO3. The shape, width and magnitude of the temperature dependence of the magnetic entropy change ($\Delta S_{m}$) for these multilayer samples can be tuned and controlled by changing their layout. A large $\Delta S_{m}$ over a wide temperature range which goes beyond room temperature is observed in all samples. We observe a temperature-independent table-top-like $\Delta S_{m}$ over a temperature range as large as 100 K in the trilayer samples. La2NiMnO6 double perovskite with multiple magnetic phase transitions is the key to tuning and shaping the temperature dependence of the magnetic entropy changes to suit the requirements of several cooling cycles.