Observation of magnetic domain evolution in constrained epitaxial Ni-Mn-Ga thin films on MgO(001) substrate

Epitaxial Ni-Mn-Ga thin films have promising application potential in micro-electro-mechanical sensing and actuation systems. To date, large abrupt magnetization changes have been observed in some epitaxial Ni-Mn-Ga thin films, but their origin either from magnetically induced martensite variant reorientation (MIR) or magnetic domain evolution has been discussed controversially. In the present work, we investigated the evolutions of the magnetic domain and microstructure of a typical epitaxial Ni-Mn-Ga thin film through wide-field magneto-optical Kerr-microscopy. It is demonstrated that the abrupt magnetization changes in the hysteresis loops should be attributed to the magnetic domain evolution instead of the MIR. (c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

In this study, the magnetic domain and microstructure evolution of epitaxial Ni-Mn-Ga thin films were investigated using wide-field magneto-optical Kerr microscopy. The results showed that the abrupt magnetization changes in the hysteresis loops should be attributed to the magnetic domain evolution.