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Effect of the location of Mn sites in ferromagnetic GaMnAs on its Curie temperature

Journal Article · · Physical Review B
We report a strong correlation between the location of Mn sites in ferromagnetic Ga{sub 1-x}Mn{sub x}As measured by channeling Rutherford backscattering and by particle induced x-ray emission experiments and its Curie temperature. The concentrations of free holes determined by electrochemical capacitance-voltage profiling and of uncompensated Mn{sup ++} spins determined from SQUID magnetization measurements are found to depend on the concentration of unstable defects involving highly mobile Mn interstitials. This leads to large variations in T{sub c} of Ga{sub 1-x}Mn{sub x}As when it is annealed at different temperatures in a narrow temperature range. The fact that annealing under various conditions has failed to produce Curie temperatures above {approx}110K is attributed to the existence of an upper limit on the free hole concentration in low-temperature-grown Ga{sub 1-x}Mn{sub x}As.
Research Organization:
Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
Sponsoring Organization:
USDOE Director. Office of Science. Office of Basic Energy Sciences. Materials Science Division; National Science Foundation Grant DMR00-72897, Defense Advanced Research Projects Agency SpinS Program; 21st Century Science and Technology Fund of Indiana, Fulbright Foundation (US)
DOE Contract Number:
AC03-76SF00098
OSTI ID:
837397
Report Number(s):
LBNL--49438
Journal Information:
Physical Review B, Journal Name: Physical Review B Journal Issue: 20 Vol. 65
Country of Publication:
United States
Language:
English

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