Effect of lattice mismatch on chemical ordering of epitaxial L1 FePt films

The effect of lattice mismatch on the chemical ordering of epitaxial FePt films was studied. The results showed that the lattice constant (c) of the FePt films decreased with increasing lattice mismatch ε from about 2.23% to 6.33%. Upon further increase of ε to about 8.8%, c increased. On the other hand, the variation of the lattice constant (a) of the FePt films showed a reversal behavior to that of c with the increased lattice mismatch. The ratio c∕a of the FePt films held a minimum of about 0.9466, while the chemical ordering degree and magnetic anisotropy constant held maximum values for ε around 6.33%. These results indicated that the strain from the lattice mismatch favored the ordering of the FePt films.