Austenite arrest in polycrystalline Ni-Mn-Co-In films

- Resistivity measurements on polycrystalline Ni-Co-Mn-In film under magnetic field.
- Austenite arrest in polycrystalline Ni45.2Co4.7Mn36.2In13.9 film.
- Field-induced reverse martensitic transformation analysis inside the hysteresis.
- Analysis of the magnetoresistance in the forward or reverse path of transformation.

Electrical resistivity and magnetization measurements realized on polycrystalline Ni45.2Co4.7Mn36.2In13.9 film showed that the austenite phase was blocked upon a magnetic field during the martensitic transformation. Besides, the shift of the temperature transition upon a magnetic field towards the lower temperature is responsible for a large magnetoresistance that can be irreproducible in the heating branch of the transformation and that was measured in this work. We studied how the magnetoresistance was changing inside the hysteresis loop depending on whether the temperature lies on the forward or reverse transformation path. The analysis is interpreted in terms of the non equilibrium state consequent to the field cooled process and how martensite is converted into austenite inside the hysteresis loop when the magnetic field is applied.