Magnetic domain imaging of ferromagnetic GaMnAs films

Scanning Hall probe microscopy has been used to study the magnetic domain structure of GaMnAs thin films after various low temperature anneals to increase the Curie temperature (TC). Samples with in-plane magnetization, which received short low temperature anneals in vacuum directly after growth, ex...

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Bibliographic Details
Published in:Journal of applied physics 2004-06, Vol.95 (11), p.7399-7401
Main Authors: Pross, Alexander, Bending, Simon, Edmonds, Kevin, Campion, R. P., Foxon, C. T., Gallagher, Bryan
Format: Article
Language:English
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Summary:Scanning Hall probe microscopy has been used to study the magnetic domain structure of GaMnAs thin films after various low temperature anneals to increase the Curie temperature (TC). Samples with in-plane magnetization, which received short low temperature anneals in vacuum directly after growth, exhibit very small (∼2–5 μm) rather random domains. In stark contrast similar samples, which additionally received very long low temperature anneals in air, display large (10–100 μm) domains, which still contain clearly resolvable magnetic disorder. Preliminary scans of air-annealed samples with out-of-plane magnetization also reveal a very irregular, rather fine (1–3 μm) domain structure. In all samples micron-sized regions at domain walls frequently remain ferromagnetic well above the average TC, indicating either the presence of ferromagnetic precipitates (e.g., MnAs) or material there with higher than average Mn concentration.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.1669113