Metamagnetic transitions and magnetocaloric effect in epitaxial Ni-Co-Mn-In films

Due to their large strains and multifunctionality, magnetic shape memory alloys are of particular interest for microsystems. Here epitaxially grown metamagnetic Ni-Co-Mn-In films on MgO (001) are analyzed which exhibit a magnetically induced austenite transition. This opens the way to use Ni-Co-Mn-In films in microactuators combining high stroke with high forces. Additionally these films exhibit an inverse magnetocaloric effect with an entropy change of 8.8 J kg(-1) K(-1) in 9 T at 353 K. The high surface-to-volume fraction of films promises a fast heat exchange, which is beneficial for efficient magnetic cooling. (C) 2010 American Institute of Physics. [doi:10.1063/1.3517443]