Magnetic characterization of intermetallic compound FePt and FePtX (X=B, Ni) thin films

VSM rotational transverse magnetization technique was used to characterize the anisotropy field of FePt and FePtX (X=B, Ni) thin films with comparison to commercial CoCrTaPt media. Anisotropy energy was derived. H c /H k was used as an indicator for coherent rotation of a single domain. Interactions between magnetic domains were characterized by Kelly–Henkel plot. Interactive field factor was used as a coupling factor similar to δM. Correlations between coercive force, magnetic anisotropy of grains, and the degree of magnetic isolation among grains were discussed. B and Ni had been added as diluting agent to the FePt system to decrease saturation magnetization, coercivity, anisotropy field and anisotropy energy. These doping elements also decrease the magnetic coupling between neighboring domains, and promote coherent rotation inside each domain.