Grain size reduction and magnetic properties improvement by in-situ annealing of FePt epitaxial thin films

FePt thin films were epitaxially grown by RF sputtering on MgO (1 0 0) substrates at 550 1C, followed by in situ annealing at the sametemperature. The in situ annealing was found to improve the magnetic characteristics: i.e., the increase in magnetic squareness up to 0.9and increase in the ratio between anisotropy and coercivity (e ¼ anisotropy field/coercive field ¼ 35.9 for 115 min annealing).Remarkably, a decrease in grain size was also found to occur by increasing the annealing time.r 2007 Elsevier B.V. All rights reserved.