  We report a strong size dependence of coercivity in amorphous ferrimagnetic
TbFeCo films. The as-deposited film exhibited a low saturation magnetization
(Ms=100 emu/cc) and a high perpendicular anisotropy (Ku=10^6 erg/cc). Hall-bar
devices were fabricated for characterizing the magneto-transport behaviors. A
significant increase in coercivity (up to 300 %) was observed at room
temperature as the width of Hall bar was reduced. The large coercivity
enhancement was attributed to the relaxation of film stress. The effect of
strain and dimensionality on the coercivity in TbFeCo makes it attractive for
tunable coercivity and the magnetization reversal in future nanoscale devices.
