Magnetization reversal process in FePt nanoparticles

In this study, the anomalous Hall effect (AHE) of a lithographically fabricated single FePt [001] nanodot and epitaxially grown FePt [001] nanoparticle arrays is measured and their magnetization reversal processes are discussed. Results show that the magnetization reversal for the nanodots initiated by the nucleation of a small reversed embryo with exchange length scale. As for the nanoparticle arrays, a change of reversal mode from coherent to incoherent rotation is observed and it is concluded that the critical size for coherent rotation in the nanoparticles is about 20 nm.