Synthesis, characterization, and modeling of high quality ferromagnetic Cr-doped AlN thin films

We report a theoretical and experimental investigation of Cr-doped AlN. Density functional calculations predict that the isolated Cr t2 defect level in AlN is 1/3 full, falls approximately at midgap, and broadens into an impurity band for concentrations over 5%. Substitutional Al1−xCrxN random alloy...

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Bibliographic Details
Published in:Applied physics letters 2003-05, Vol.82 (18), p.3047-3049
Main Authors: Wu, Stephen Y., Liu, H. X., Gu, Lin, Singh, R. K., Budd, L., van Schilfgaarde, M., McCartney, M. R., Smith, David J., Newman, N.
Format: Article
Language:English
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Summary:We report a theoretical and experimental investigation of Cr-doped AlN. Density functional calculations predict that the isolated Cr t2 defect level in AlN is 1/3 full, falls approximately at midgap, and broadens into an impurity band for concentrations over 5%. Substitutional Al1−xCrxN random alloys with 0.05⩽x⩽0.15 are predicted to have Curie temperatures over 600 K. Experimentally, we have characterized and optimized the molecular beam epitaxy thin film growth process, and observed room temperature ferromagnetism with a coercive field, Hc, of 120 Oe. The measured magnetic susceptibility indicates that over 33% of the Cr is magnetically active at room temperature and 40% at low temperature.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.1570521