Promotion of L10 ordered phase transformation by the Ag top layer on FePt thin films

The influence of the deposition of an ultrathin Ag top layer on the structure and magnetic properties of FePt thin films has been investigated. Crystallographic ordering of the L1(0) face-centered-tetragonal (fct) FePt phase was significantly promoted when a Ag layer was deposited on top of the film. The increased fraction of hard magnetic L1(0) fct FePt phase led to a dramatic increase of coercivity from 1 to about 6.0 kOe. The deltaM curves suggested exchange decoupling of magnetic grains. A perpendicular FePt film with a coercivity of 5.0 kOe and remanent squareness of 0.98 was achieved with a CrRu underlayer and the Ag top layer. (C) 2003 American Institute of Physics.