Temperature dependence of FePt thin film growth on MgO(100)

FePt films have been prepared by pulsed laser deposition onto MgO(001) substrates at room temperature and at high temperatures of 700 and 800 degrees C. Epitaxial growth is observed down to room temperature, which has not been reported before and which is explained by the high energy deposition process. Chemical ordering, on the other hand, occurs only at higher temperatures. The c-axis of the L1(0) phase is perpendicular to the substrate for the highest deposition temperature of 800 degrees C and both in-plane/out-of-plane for the partially ordered films deposited at lower temperatures. It is shown that the out-of-plane orientation of the c-axis is favored and a state of complete out-of-plane ordering can be reached during annealing if the film is granular after deposition. In this case, the magnetic properties are comparable to films deposited at high temperature, with coercivities above 5 T. If the film is continuous, however, the pure perpendicular c-axis texture is suppressed due to accumulation of compressive stress. (c) 2006 Elsevier B.V. All rights reserved.