Improvement of hard magnetic properties in microfabricated L10-FePt dot arrays upon post-annealing

Epitaxial L1(0)-FePt (001) dot arrays were fabricated through the use of a microfabrication process. The lateral size of square dots was changed in the range of 0.2 to 5 mu m. The coercivity (H-C) increased after patterning a continuous film to dot arrays. Furthermore, H-C was drastically enhanced by post-annealing, and H-C exceeding 20 kOe was achieved for the dots with 0.2 x 0.2 mu m(2) annealed at 600 degrees C, in contrast to the continuous film showing low H(C)of 1kOe. The enhancement of H. for dot arrays upon annealing was attributed to the decrease of structure defects caused by the damage due to the microfabrication, which provide the nucleation sites where reversed domains are generated at a low field.