Giant low-field magnetocaloric effect and refrigerant capacity in reduced dimensionality EuTiO3 multiferroics

Abstract

Engineering magnetic materials into a thin film form while preserving its excellent magnetocaloric response is essential in the development of miniature magnetic coolers. We demonstrate how this can be achieved in the case of EuTiO3 – an emerging multiferroic material. Unlike conventional cases where reduced dimensionality considerably decreased the magnetic entropy change (ΔSM) and hence the refrigerant capacity (RC), we show the large low-field enhancements of ΔSM and RC in a ∼100 nm thick nanocrystalline EuTiO3 film (ΔSM ∼ 24 J kg−1K−1 and RC = 152 J kg-1 for μ0ΔH = 2 T) relative to its single crystal counterpart (ΔSM ∼ 17 J kg−1K−1 and RC ∼ 107 J kg-1 for μ0ΔH = 2 T). The nanocrystalline EuTiO3 film is an excellent candidate for cryogenic magnetic refrigeration. From our study, a new approach for improving both MCE and RC in magnetic nanomaterials is proposed, which will stimulate further research on magnetocaloric thin films and related cooling devices.