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The Hall effect and hole densities in high Tc GaMnAs thin films

K. W. Edmonds, K. Y. Wang, R. P. Campion, A. C. Neumann, C. T. Foxon, B. L. Gallagher, P. C. Main

cond-mat.mtrl-sciarXiv:cond-mat/0205517

Abstract

By studying the Hall effect in a series of low resistivity Ga1-xMnxAs samples, accurate values for the hole density p, Mn concentration x, and Curie temperature Tc are obtained over the range 0.015=<x=<0.08. The hole density corresponds to 90% of the Mn concentration at low x, and has a maximum value of 1.0x10-27 m-3 when Tc=125K for x=0.06. This data allows the first meaningful comparison of mean field predicted Curie temperatures with experiment over a wide range of x. The theory is in qualitative agreement with experiment, but overestimates Tc at large x and underestimates TC at low x.

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