Determination of the Mn concentration in GaMnAs

Zhao, Lixia; Campion, R. P.; Fewster, Paul F.; Martin, Robert; Ber, B. Ya.; Kovarsky, A.P.; Staddon, C. R.; Wang, K Y; Edmonds, K. W.; Foxon, C.T.; Gallagher, B. L.

doi:10.1088/0268-1242/20/5/008

Cited by 23 publications

(11 citation statements)

References 18 publications

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“…A detailed comparison of the results of a number of different calibration techniques, presented in Ref. 62, allows us to assign an uncertainty of ±10% to the quoted Mn concentrations. However, it should be noted that the SIMS measurements yield the total volume density of Mn in the ͑Ga,Mn͒As films, and not the fraction of Ga substituted by Mn.…”

Section: Experiments a Measured Curie Temperatures And Hole Densmentioning

confidence: 99%

Prospects for high temperature ferromagnetism in (Ga,Mn)As semiconductors

et al. 2005

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We report on a comprehensive combined experimental and theoretical study of Curie temperature trends in ͑Ga,Mn͒As ferromagnetic semiconductors. Broad agreement between theoretical expectations and measured data allows us to conclude that T c in high-quality metallic samples increases linearly with the number of uncompensated local moments on Mn Ga acceptors, with no sign of saturation. Room temperature ferromagnetism is expected for a 10% concentration of these local moments. Our magnetotransport and magnetization data are consistent with the picture in which Mn impurities incorporated during growth at interstitial Mn I positions act as double-donors and compensate neighboring Mn Ga local moments because of strong nearneighbor Mn Ga u Mn I antiferromagnetic coupling. These defects can be efficiently removed by post-growth annealing. Our analysis suggests that there is no fundamental obstacle to substitutional Mn Ga doping in high-quality materials beyond our current maximum level of 6.8%, although this achievement will require further advances in growth condition control. Modest charge compensation does not limit the maximum Curie temperature possible in ferromagnetic semiconductors based on ͑Ga,Mn͒As.

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Section: Experiments a Measured Curie Temperatures And Hole Densmentioning

confidence: 99%

Prospects for high temperature ferromagnetism in (Ga,Mn)As semiconductors

et al. 2005

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“…In LT-MBE grown GaMnAs on GaAs there exists one additional peak for lower l which represents the larger lattice parameter of GaMnAs. 41 After implantation and PLA the inhomogeneous Mn distribution leads to a XRD ͑004͒ reflection which continuously changes between l = 3.98 and 4.00. After ten pulses the probed additional overcompensation represents an increasing imperfection of the lattice.…”

Section: Hr-xrdmentioning

confidence: 99%

Application of pulsed laser annealing to ferromagnetic GaMnAs

et al. 2010

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In this experimental and theoretical work we focus on the technique of pulsed laser annealing applied to the metastable ferromagnetic semiconductor GaMnAs. Analytical heat-flow calculations are used to illustrate the position and time-dependent temperature distribution during the whole laser annealing process. Such heat-flow calculations will also play an indispensable role for the preparation of other new metastable diluted ferromagnetic semiconductors by ion implantation and subsequent laser annealing. The structural, magnetic, and magnetotransport properties of ferromagnetic GaMnAs have been probed in dependence on the annealing parameters, e.g., the number of laser pulses and the pulse length. Annealing with a single KrF laser pulse of 30 ns and 0.26 J / cm 2 with the photon energy above the GaAs band gap energy leads to similar magnetic properties like annealing with a single 3 ns Nd:YAG laser pulse with the photon energy below the GaAs band gap energy. We observed that possibly due to Mn diffusion and decreasing hole concentration, several laser pulses degrade the structural and magnetic properties of GaMnAs. Our results reveal the largest saturation magnetization in Mn-implanted GaAs annealed with a single KrF laser pulse.

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“…However, the growth of dilute magnetic semiconductors [11] or of non-stoichiometric GaAs for ultrafast photoconductive devices [12] requires substrate temperatures below 300 1C. In order to avoid systematic errors, it is essential that a reproducible measurement can be performed routinely over a temperature range from 200 to 660 1C without realigning optical components or switching from one measurement technique to another.…”

Section: Temperature Measurement On Undoped Substratesmentioning

confidence: 99%