UC Berkeley

We present a detailed investigation of the magnetic and magnetotransport properties of thin films of ferromagnetic Ga1-x Mnx As synthesized using ion implantation and pulsed-laser melting (II-PLM). The field and temperature-dependent magnetization, magnetic anisotropy, temperature-dependent resistivity, magnetoresistance, and Hall effect of II-PLM Ga1-x Mnx As films have all of the characteristic signatures of the strong p-d interaction of holes and Mn ions observed in the dilute hole-mediated ferromagnetic phase. The ferromagnetic and electrical transport properties of II-PLM films correspond to the peak substitutional Mn concentration meaning that the nonuniform Mn depth distribution is unimportant in determining the film properties. Good quantitative agreement is found with films grown by low temperature molecular beam epitaxy and having the similar substitutional MnGa composition. Additionally, we demonstrate that II-PLM Ga1-x Mnx As films are free from interstitial MnI because of the high-temperature processing. At high Mn implantation doses, the kinetics of solute redistribution during solidification alone determine the maximum resulting MnGa concentration. Uniaxial anisotropy between in-plane [1- 10] and [110] directions is present in II-PLM Ga1-x Mnx As giving evidence for this being an intrinsic property of the carrier-mediated ferromagnetic phase. © 2008 American Institute of Physics.