Guillaume Crouigneau

Ni-Co-Mn-In films Guillaume Crouigneau

Heusler alloys have interesting mechanical, magnetic and thermal properties that result from the martensite-austenite structural transition. The coupling of these properties leads to applications in the field of actuators, sensors or coolers. We have developed a Ni-Co-Mn-In type film using a co-sputtering process. The objective is to obtain a film with a structural and magnetic transition at room temperature. After the study of the structure and the microstructure of the martensite and austenite phases, the magnetic properties were investigated. The change of magnetic state obtained for some films during the first order transition has led to interesting magnetocaloric and actuation properties. The best results are obtained for a film of composition Ni45.2Co4.7Mn36.2In13.9. The resistivity measurements under intense magnetic field is an innovative subject on films of this type and leads to a study of the irreversibility and the blocking of the structural transformation induced by the magnetic field (kinetic arrest).