Sputtered FeHfO films with high electrical resistivity and good soft magnetic properties

Akihiro Makino, Yasuo Hayakawa

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


The microstructures, magnetic properties and electrical resistivities ρ{variant} of FeHfO films with solute content of 2.1-22.7 at.% Hf and 7.8-41.6 at.% O prepared by r.f. magnetron sputtering technique in an ArO2 mixed atmosphere were investigated. A structure composed of a b.c.c. phase and an amorphous phase is found to be formed in the compositional range 10 at.% ≤Hf and 5 ≤ O ≤ 36 at.% for the as-deposited films. The fraction of the amorphous phase containing a large amount of O, which produces a high ρ{variant}, increases the size of the b.c.c. grains decreases with increasing Hf content. The films with an O-to-Hf ratio of 3.2-4.0 show low coercivities of 30-100 A m-1 in the as-deposited state and also good soft magnetic properties after annealing under optimum conditions which do not cause a substantial change in the as-deposited structure. An Fe54.9Hf11O34.1 film annealed for 21.6 ks at 673 K in a rotating field of 160 kA m-1 exhibits a Bs of 1.2 T, an Hc of 64 A m-1 and a |μ| at 50 MHz of 1800 owing to a high ρ{variant} value of 8 μω m. This value of |μ| for the film is superior to those for already-known metallic soft magnetic films. Therefore the FeHfO films are expected to be useful for the core material of micromagnetic devices in the high frequency range.

Original languageEnglish
Pages (from-to)1020-1024
Number of pages5
JournalMaterials Science and Engineering A
Issue numberC
Publication statusPublished - 1994 May 15
Externally publishedYes

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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