Curie temperature and carrier concentration gradients in MBE grown GaMnAs layers

Abstract

We report on detailed investigations of the electronic and magnetic properties of ferromagnetic GaMnAs layers, which have been fabricated by low-temperature molecular-beam epitaxy. Superconducting quantum interference device measurements reveal a decrease of the Curie temperature from the surface to the GaMnAs/GaAs interface. While high resolution x-ray diffraction clearly shows a homogeneous Mn distribution, a pronounced decrease of the carrier concentration from the surface towards the GaMnAs/GaAs interface has been found by Raman spectroscopy as well as electrochemical capacitance-voltage profiling. The gradient in Curie temperature seems to be a general feature of GaMnAs layers grown at low-temperature. Possible explanations are discussed.

3 pages, 4 figures, submitted to APL

References in corpus (2)

• Effects of annealing time on defect-controlled ferromagnetism in Ga1-xMnxAs
• High Curie temperature GaMnAs obtained by resistance-monitored annealing

Cited by in corpus (7)

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• Anomalous behavior of spin wave resonances in Ga_{1-x}Mn_{x}As thin films
• Effect of annealing on the depth profile of hole concentration in (Ga,Mn)As
• Magnetocrystalline anisotropy and magnetization reversal in GaMnP synthesized by ion implantation and pulsed-laser melting
• Magnetization of ultrathin (Ga,Mn)As layers
• Enhancement of the Curie temperature in GaMnAs/InGaMnAs superlattices
• Electronic and magnetic properties of GaMnAs: Annealing effects