CONTROLLING REVERSIBILITY OF THE MAGNETO-STRUCTURAL TRANSITION IN FIRST-ORDER MATERIALS ON THE MICRO SCALE

摘要

Materials with structural first-order transformations that coincide with a drastic change in magnetization are interesting for magnetocaloric applications. The theoretical cooling capacity of these materials is high, but during a cyclic application, the ongoing formation and moving of phase boundaries dissipates valuable energy. We propose a route to decrease the hysteresis by shifting the transformation temperature locally and preserving nuclei of the low-temperature phase. As a model system we use epitaxial Ni-Mn-Ga films. Thin films may also find a field of application in micro-systems.