Coexistence of Mn2+ and Mn3+ in ferromagnetic GaMnN

S. Sonoda, I. Tanaka, H. Ikeno, T. Yamamoto, F. Oba, T. Araki, Y. Yamamoto, K. Suga, Y. Nanishi, Y. Akasaka, K. Kindo, H. Hori

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Abstract

Considerable efforts have been devoted recently to synthesizing diluted magnetic semiconductors having ferromagnetic properties at room temperature because of their technological impacts for spintronic devices. In 2001 successful growth of GaMnN films showing room temperature ferromagnetism and p-type conductivity was reported. The estimated Curie temperature was 940 K at 5.7% of Mn, which is the highest among diluted magnetic semiconductors ever reported. However, the electronic mechanism behind the ferromagnetic behaviour has still been controversial. Here we show experimental evidence using ferromagnetic samples that Mn atoms are substitutionally dissolved into the GaN lattice and they exhibit mixed valences of +2 (majority) and +3. The p-type carrier density decreases significantly at very low temperatures. At the same time, magnetization dramatically decreases. The results imply that the ferromagnetic coupling between Mn atoms is mediated by holes in the mid-gap Mn band.

Original languageEnglish
Pages (from-to)4615-4621
Number of pages7
JournalJournal of Physics Condensed Matter
Volume18
Issue number19
DOIs
Publication statusPublished - 2006 May 17

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

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    Sonoda, S., Tanaka, I., Ikeno, H., Yamamoto, T., Oba, F., Araki, T., Yamamoto, Y., Suga, K., Nanishi, Y., Akasaka, Y., Kindo, K., & Hori, H. (2006). Coexistence of Mn2+ and Mn3+ in ferromagnetic GaMnN. Journal of Physics Condensed Matter, 18(19), 4615-4621. https://doi.org/10.1088/0953-8984/18/19/015