Influence of surface treatment on the magnetic properties of GaxMn1-xAs thin films

We present a surface science study on carefully characterized GaxMn1-xAs films grown on GaAs(100), where we investigate the influence on magnetic properties of different surface cleaning procedures. X-ray magnetic circular dichroism reveals a net remnant magnetization along the (100) axis, after chemical etching is performed. The analysis of Mn L-2,L-3 XAS line shapes in different environment indicates that Mn in GaxMn1-xAs behaves as a bulk impurity. By exploiting the different depth sensitivity between x-ray photoemission and x-ray absorption we observe the presence of a Mn depleted layer at the surface after etching.