Ni1-xCox-C nanogranular thin films prepared by a co-sputtering method: Improvement in magnetic properties by optimizing the alloy ratio

Satoshi Tomita, Hiroaki Adachi, Minoru Fujii, Shinji Hayashi

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Nanogranular thin films consisting of Ni1-xCox alloy nanoparticles separated by graphitic matrices are fabricated by a co-sputtering method. The structure and magnetic properties of the films are studied. An improvement in their magnetic properties by optimizing the alloy ratio will be demonstrated. Transmission electron microscopic (TEM) observation shows nanoparticles with a small mean diameter (∼ 7 nm) and narrow size distribution (∼ 20% of mean diameter) at the Co/(Ni + Co) ratio (x) ranging from 0 to 0.83. In this region, the coercivity continuously increases with x and manifests a maximum value of 907 Oe at x = 0.83. The increase can be explained in terms of alloy formation. With further increasing x up to x = 1, the coercivity decreases. The decrease is caused by the existence of extremely large Co particles, which are revealed by TEM observation.

Original languageEnglish
Pages (from-to)6370-6374
Number of pages5
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume40
Issue number11
DOIs
Publication statusPublished - 2001 Nov
Externally publishedYes

Keywords

  • Co-sputtering method
  • Graphitic matrices
  • Magnetic properties
  • Magnetic recording media
  • Nanogranular thin film

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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