Mn valence state mediated room temperature ferromagnetism in nonpolar Mn doped GaN

P. V. Wadekar, C. W. Chang, Y. J. Zheng, S. S. Guo, W. C. Hsieh, C. M. Cheng, M. H. Ma, W. C. Lai, J. K. Sheu, Q. Y. Chen, L. W. Tu

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Abstract

In this work, we demonstrate room temperature ferromagnetism in nonpolar, m-plane manganese doped gallium nitride (m-GaN:Mn) epitaxial thin films synthesized using plasma-assisted molecular beam epitaxy on nonpolar, m-plane sapphire (Al 2 O 3 ) substrates. We observed that Mn doping concentration plays a key role in stabilizing the valence state of Mn ions thereby influencing the magnetic and transport properties. Chemical characterization by X-ray photoelectron spectroscopy, X-ray absorption near edge spectra, and energy dispersive X-ray spectroscopy affirm homogeneous valence state Mn +3 in lightly doped samples, while higher doping levels cause a heterogeneous Mn +0 and Mn +2 mixed valence states. Magnetic measurements indicate that films with low doping levels show the signature of room temperature ferromagnetism, while films with higher doping show antiferromagnetic/spin glass behavior besides the indication of MnGa alloys. Temperature dependent resistivity measurements show that both the samples are semiconducting with deep level defect states. Our findings suggest the possibility of incorporating spin functionality in non-polar optoelectronic devices.

Original languageEnglish
Pages (from-to)693-698
Number of pages6
JournalApplied Surface Science
Volume473
DOIs
Publication statusPublished - 2019 Apr 15

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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    Wadekar, P. V., Chang, C. W., Zheng, Y. J., Guo, S. S., Hsieh, W. C., Cheng, C. M., Ma, M. H., Lai, W. C., Sheu, J. K., Chen, Q. Y., & Tu, L. W. (2019). Mn valence state mediated room temperature ferromagnetism in nonpolar Mn doped GaN. Applied Surface Science, 473, 693-698. https://doi.org/10.1016/j.apsusc.2018.12.163