Evidence Of Metallic Clustering In Annealed Ga1-Xmnxas From Atypical Scaling Behavior Of The Anomalous Hall Coefficient

The anomalous Hall coefficient (R-s) and longitudinal resistivity (rho(xx)) scaling relationship (R-S=c rho(n)(xx)) for a series of annealed Ga1-xMnxAs epilayers (x approximate to 0.055) are investigated. As-grown samples exhibit a scaling parameter n similar to 1 and samples annealing near the optimal annealing temperature, n similar to 2. For annealing temperatures far above the optimum they observe scaling with n>3, which is similar to the behavior of certain inhomogeneous systems. Optical spectroscopy measurements also reveal an enhancement of the absorption coefficient in these samples for photons of energy around 1 eV. These atypical behaviors are characteristic of spherical resonance from metallic inclusions. (c) 2006 American Institute of Physics.