EPL, 78 (2007) 37006
DOI: 10.1209/0295-5075/78/37006

Evidence for carrier-induced high- ferromagnetism in Mn-doped GaN film

S. Yoshii¹, S. Sonoda², T. Yamamoto¹, T. Kashiwagi¹, M. Hagiwara¹, Y. Yamamoto³, Y. Akasaka⁴, K. Kindo⁵ and H. Hori<sup>3

1</sup>  KYOKUGEN, Osaka University - 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
²  Department of Electronics and Information Science, Kyoto Institute of Technology - Kyoto 606-8585, Japan
³  School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST) - 1-1 Asahidai Tatsunokuchi, Ishikawa 923-1292, Japan
⁴  Department of System Innovation, Osaka University - Toyonaka, Osaka 560-8531, Japan
⁵  Institute for Solid State Physics, University of Tokyo - Kashiwa 277-8581, Japan

yoshii@mag.cqst.osaka-u.ac.jp

received 29 December 2006; accepted in final form 27 March 2007; published May 2007
published online 27 April 2007

Abstract
A GaN film doped with 8.2% Mn was grown by the molecular-beam-epitaxy technique. Magnetization measurements show that this highly Mn-doped GaN film exhibits ferromagnetism above room temperature. It is also revealed that the high-temperature ferromagnetic state is significantly suppressed below 10 K, accompanied by an increase of the electrical resistivity with decreasing temperature. This observation clearly demonstrates a close relation between the ferromagnetism with extremely high and the carrier transport in the Mn-doped GaN film.

PACS
75.50.Pp - Magnetic semiconductors.
73.50.-h - Electronic transport phenomena in thin films.
73.61.Ey - III-V semiconductors.

© Europhysics Letters Association 2007