A Hall coefficient investigation of ferromagnetic Ga 1- xMn xAs layers on (100) GaAs substrates
Abstract
Ferromagnetic Ga 1- xMn xAs epilayers with Mn mole fraction in the range of x≈2.2-4.4% were grown on semi-insulating (100) GaAs substrates using the molecular beam epitaxy technique. The transport properties of these epilayers were investigated through Hall effect measurements. The measured hole concentration of Ga 1- xMn xAs layers varied from 4.4×10 19 to 3.4×10 19 cm -3 in the range of x≈2.2-4.4% at room temperature. From temperature dependent resisitivity data, the sample with x≈4.4% shows typical behavior for insulator Ga 1- xMn xAs and the samples with x≈2.2 and 3.7% show typical behavior for metallic Ga 1- xMn xAs. The Hall coefficient for the samples with x≈2.2 and 4.4% was fitted assuming a magnetic susceptibility given by Curie-Weiss law in a paramagnetic region. This model provides good fits to the measured data up to T=300 K and the Curie temperature Tc was estimated to be 65, 83 K and hole concentration p was estimated to be 5.1×10 19, 4.6×10 19 cm -3 for the samples with x≈2.2 and 4.4%, respectively, confirming the existence of an anomalous Hall effect for metallic and insulating samples.
- Publication:
-
Solid State Communications
- Pub Date:
- June 2004
- DOI:
- 10.1016/j.ssc.2004.02.054
- Bibcode:
- 2004SSCom.130..627Y