Ion Irradiation-Induced Magnetic Transition of MnGa Alloy Films Studied by X-Ray Magnetic Circular Dichroism and Low-Temperature Hysteresis Loops

D. Oshima, M. Tanimoto, T. Kato, Y. Fujiwara, T. Nakamura, Y. Kotani, S. Tsunashima, S. Iwata

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

The ion irradiation-induced magnetic transition of L10-MnGa alloy films was studied in detail by measuring X-ray magnetic circular dichroism (XMCD) and the temperature dependence of their hysteresis loops. The XMCD of (001)-oriented MnGa films exhibited different spectral shapes depending on whether magnetization was parallel or perpendicular to the film plane; that is considered to be the origin of the large perpendicular magnetic anisotropy of the L10-MnGa. The anisotropy of XMCD spectra was not influenced by the ion irradiation to the MnGa, while the intensity of the XMCD signal decreased with increasing ion dose. From the measurement of hysteresis loops at low temperature, the significant increase of coercivity Hc in the ion-irradiated MnGa was found by lowering the temperature, while only a slight increase of Hc was observed in the as-prepared MnGa. These results suggest that the ion-irradiated MnGa film has a composite structure of L10-ordered MnGa nanocrystals separated by an A1-disordered MnGa matrix, and that increasing the ion dose results in an increase in the volume ratio of A1-MnGa to L10-MnGa in the film.

Original languageEnglish
Article number7401048
JournalIEEE Transactions on Magnetics
Volume52
Issue number7
DOIs
Publication statusPublished - 2016 Jul
Externally publishedYes

Keywords

  • Bit-patterned media (BPM)
  • MnGa
  • X-ray magnetic circular dichroism (XMCD)
  • ion irradiation

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

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