Compositional inhomogeneity in electroless-deposited CoNiP films studied by spin-echo 59Co nuclear magnetic resonance

Takayuki Homma, Yuji Sezai, Tetsuya Osaka, Yasushi Maeda, David M. Donnet

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21 Citations (Scopus)

Abstract

A compositionally inhomogeneous state in electroless-deposited CoNiP films with perpendicular magnetic anisotropy is investigated using spin-echo 59Co nuclear magnetic resonance (NMR), focusing on its correlation with magnetic properties. By adjusting pH of the electroless-deposition bath, films were prepared which possess almost the same average composition (Co42Ni50P8) and crystal orientation, but the differing values of coercivity (Hc). By analyzing the shift in peak resonance frequency of NMR spectra of the CoNiP films with respect to that of bulk CoNi alloys, we observed the formation of a compositionally inhomogeneous state in the film which possesses high Hc of 2600 Oe, whereas formation of inhomogeneities was not observed for the low-Hc films. By assuming that a Co-enriched ferromagnetic component detected by NMR was separated from a non-magnetic amorphous Ni-P component, we found that the high-Hc film consists of Co42Ni26 and Ni24P8. Moreover, the results of high spatial resolution X-ray microanalysis on the high-Hc film showed a tendency that the Co-enriched ferromagnetic component segregates to the center of grains and the Ni-P non-magnetic component segregates to grain boundaries. Such evidence indicates that compositional inhomogeneities could be one of the origins of high-Hc in CoNiP films.

Original languageEnglish
Pages (from-to)314-320
Number of pages7
JournalJournal of Magnetism and Magnetic Materials
Volume173
Issue number3
Publication statusPublished - 1997 Sep

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Keywords

  • Compositional inhomogeneity
  • Electroless-deposited films
  • High-coercivity films
  • Magnetic recording media
  • Spin-echo Co nuclear magnetic resonance

ASJC Scopus subject areas

  • Condensed Matter Physics

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