Morphology and magnetic properties of Pt/Co/Pt/Al2O3(0001) structures:: influence of the growth temperature

We have studied the influence of growth temperature on the morphology and magnetic properties of a cobalt layer covered by a platinum layer grown on Pt(40 Angstrom)/Al2O3(0001). The morphology of the Pt/Co/Pt trilayer thus obtained depends strongly on the growth temperature of the two upper layers of the structure. This is due to modifications of the growrh of the cobalt layer with temperature. Changing the growth temperature of the two upper layers of the structure leads to a great modification of the morphology of the cobalt layer. At low temperature (100 degrees C), the morphology of the cobalt layer is nearly independent of the cobalt thickness. Ar high temperature (400 degrees C), thick Co layers are constituted of a quasi-continuous cobalt layer over which grow large three-fold symmetrical islands of cobalt. These changes of the morphology correspond to important modifications in the magnetic anisotropy and coercivity of the Pt/Co/Pt trilayers, (C) 1998 Published by Elsevier Science B.V. All rights reserved.