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β-Detected \NMR\ Search for Magnetic Phase Separation in Epitaxial GaAs:Mn

Titleβ-Detected \NMR\ Search for Magnetic Phase Separation in Epitaxial GaAs:Mn
Publication TypeJournal Article
Year of Publication2012
AuthorsSong, Q, Chow, KH, Miller, RI, Fan, I, Hossain, MD, Kiefl, RF, Morris, GD, Kreitzman, SR, Levy, CDP, Parolin, TJ, Pearson, MR, Salman, Z, Saadaoui, H, Smadella, M, Wang, D, Yu, KM, Liu, X, Furdyna, JK, MacFarlane, WA
JournalPhysics Procedia
Pagination174 - 177
Keywordslow energy muons

To test for the microscopic magnetic phase separation in the dilute magnetic semiconductor Ga1−xMnxAs sug-gested by low energy muon spin rotation measurements[1], we present a detailed analysis of the amplitudes of the 8Li β-detected nuclear magnetic resonance in an epitaxially grown thin film of x = 5.4% Mn doped GaAs on a semi-insulating GaAs substrate with magnetic transition temperature \{TC\} =72 K. The spectrum at 100 K corresponds to 73% of the full room temperature amplitude, and at 60 K to about 62%. The 11% loss of signal through the magnetic tran-sition is much smaller than that ∼ 50% found by low energy μSR[1], and may be entirely due to an amplitude change intrinsic to GaAs. This lack of evidence for phase separation is, however, consistent with the full volume fraction magnetism found by a second low energy μSR measurement on a different sample using weak transverse field[2].