GaN:Gd: A superdilute ferromagnetic semiconductor with a Curie temperature above 300 K

Abstract

We investigate the magnetic and magneto-optic properties of epitaxial GaN:Gd layers as a function of the external magnetic field and temperature. An unprecedented magnetic moment is observed in this diluted magnetic semiconductor. The average value of the moment per Gd atom is found to be as high as 4000 \mub as compared to its atomic moment of 8 \mub. The long-range spin-polarization of the GaN matrix by Gd is also reflected in the circular polarization of magneto-photoluminescence measurements. Moreover, the materials system is found to be ferromagnetic above room temperature in the entire concentration range under investigation (7$\times 10^{15}$ to 2$\times 10^{19}$ cm${}^{-3}$). We propose a phenomenological model to understand the macroscopic magnetic behavior of the system. Our study reveals a close connection between the observed ferromagnetism and the colossal magnetic moment of Gd.

References in corpus (3)

• Ferromagnetism in Fe-doped SnO2 thin films
• High Temperature Ferromagnetism with Giant Magnetic Moment in Transparent Co-doped SnO2-d
• The continuum percolation threshold for interpenetrating squares and cubes

Cited by in corpus (4)

• Electronic structure of rare-earth impurities in GaAs and GaN
• Tracking defect-induced ferromagnetism in GaN:Gd
• Microscopic properties of degradation-free capped GdN thin films studied by Electron Spin Resonance
• Anisotropic defect-induced ferromagnetism and transport in Gd-doped GaN two-dimensional electron gasses