Epitaxial Growth of Ni-Mn-Ga on Al2O3(11(Formula Presented.)0) Single-Crystal Substrates by Pulsed Laser Deposition

Pinedo-Cuba M.G.; Caicedo-Roque J.M.; Padilla-Pantoja J.; Quispe-Marcatoma J.; Landauro C.V.; Peña-Rodríguez V.A.; Santiso J. · Surfaces (2025) · DOI: 10.3390/surfaces8020035

Resumen

Magnetic shape memory alloys have attracted considerable attention due to their multifunctional properties. Among these materials, Ni-Mn-Ga alloys are distinguished by their ability to achieve up to 10% strain when exposed to a magnetic field, a characteristic predominantly observed in single-crystal samples. Consequently, it is essential to develop nanomaterials with a crystal structure closely resembling that of a single crystal. In this study, an epitaxial Ni-Mn-Ga thin film was fabricated using Pulsed Laser Deposition on an Al2O3  (Formula presented.) single-crystal substrate. The crystal structure was characterised through X-ray diffraction methodologies, such as symmetrical (Formula presented.) scans, pole figures, and reciprocal space maps. The results indicated that the sample was mainly in a slightly distorted cubic austenite phase, and some incipient martensite phase also appeared. A detailed microstructural analysis, performed by transmission electron microscopy, confirmed that certain regions of the sample exhibited an incipient transformation to the martensite phase. Regions closer to the substrate retained the austenite phase, suggesting that the constraint imposed by the substrate inhibits the phase transition. These results indicate that it is possible to grow high crystalline quality thin films of Ni-Mn-Ga by Pulsed Laser Deposition.

Instituciones: Universidad Nacional Mayor de San Marcos