Thickness dependence of magnetization reversal and magnetostriction in Fe 81 Ga 19 thin films

$M\\phantom{\\rule{0}{0ex}}a\\phantom{\\rule{0}{0ex}}g\\phantom{\\rule{0}{0ex}}n\\phantom{\\rule{0}{0ex}}e\\phantom{\\rule{0}{0ex}}t\\phantom{\\rule{0}{0ex}}o\\phantom{\\rule{0}{0ex}}s\\phantom{\\rule{0}{0ex}}t\\phantom{\\rule{0}{0ex}}r\\phantom{\\rule{0}{0ex}}i\\phantom{\\rule{0}{0ex}}c\\phantom{\\rule{0}{0ex}}t\\phantom{\\rule{0}{0ex}}i\\phantom{\\rule{0}{0ex}}o\\phantom{\\rule{0}{0ex}}n$ is a key property used in devices such as sensors, actuators, and energy harvesters, particularly in spintronics and straintronics. Here the authors perform an exhaustive magnetization-reversal study of galfenol films ranging from 5 to 60 nm in thickness, to tie the magnetic properties to film structure. The thinnest film possesses the best characteristics for potential applications: highest magnetostriction coefficient, lowest coercive and saturation fields, and pronounced anisotropy. These results should inform strain-engineering solutions for voltage control of magnetism in extrinsic multiferroics that combine piezoelectric and magnetostrictive materials.