Structure and Giant Inverse Magnetocaloric Effect of Epitaxial Ni-Co-Mn-Al Films

Abstract

The structural, magnetic, and magnetocaloric properties of epitaxial Ni-Co-Mn-Al thin films with different compositions have been studied. The films were deposited on MgO(001) substrates by co-sputtering on heated substrates. All films show a martensitic transformation, where the transformation temperatures are strongly dependent on the composition. The structure of the martensite phase is shown to be 14M. The metamagnetic martensitic transformation occurs from strongly ferromagnetic austenite to weakly magnetic martensite. The structural properties of the films were investigated by atomic force microscopy and temperature dependent X-ray diffraction. Magnetic and magnetocaloric properties were analyzed using temperature dependent and isothermal magnetization measurements. We find that Ni${}_{41}$Co${}_{10.4}$Mn${}_{34.8}$Al${}_{13.8}$ films show giant inverse magnetocaloric effects with magnetic entropy change of 17.5\,J\,kg${}^{-1}$K${}^{-1}$ for ${\mu }_0\Delta H=5\text{T}$.

arXiv comment8 pages, 8 figures

References in corpus (2)

• Adaptive modulations of martensites
• Suppression of the thermal hysteresis in magnetocaloric MnAs thin film by highly charged ion bombardment

Cited by in corpus (3)

• Nucleation and growth of hierarchical martensite in epitaxial shape memory films
• Polarized neutron channeling as a tool for the investigations of weakly magnetic thin films
• Hints on the origin of the thermal hysteresis suppression in giant magnetocaloric thin films irradiatied with highly charged ions