Magneto‐optical δM measurements of interactions in electroplated CoPt films

The codeposition of phosphorus in electroplated Co80Pt20 films strongly increases the coercive force, up to values (5000 Oe) comparable with those of bulk samples. The δM method has been applied in order to characterize the magnetic interactions among grains. Longitudinal Kerr effect measurements have been performed onto samples having a different concentration of phosphorus. Our results show that the exchange interaction among grains is absent in samples containing phosphorus; the proposed mechanism of exchange decoupling, which can also account for the increase in the coercive force, is the presence of a nonferromagnetic (or weakly ferromagnetic) phosphorus‐rich phase localized at grain boundary.

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