Structural stability of multiply twinned FePt nanoparticles

The structural stability of FePt nanoparticles in multiply twinned and single crystalline morphologies is investigated by means of molecular statics calculations based on a recently developed analytic bond-order potential. The results obtained from the atomistic calculations are used for validating a continuum model which allows the contributions of elastic strain, surface and twin boundary energies to be assessed separately. The static model calculations predict a strong energetic preference for single crystalline morphologies in the ordered L10 and disordered A1 phases. If estimates of vibrational entropy contributions are taken into account, however, icosahedral particles can become thermodynamically stable at elevated temperatures.