Atomic structure and magnetic properties of Mn on InAs(100)

We have studied Mn/InAs(001)(4x2)c(8x2) interfaces by high-resolution core-level spectroscopy, surface EXAFS and by X-ray magnetic circular dichroism (XMCD). The growth of manganese is found to depend strongly on the temperature of InAs. At low temperatures (room and liquid nitrogen temperature (LNT)), Mn atoms form the compound MnAs in the surface region leaving metallic In islands on the surface. Manganese deposition at 530K results in strong diffusion of Mn into the substrate followed by formation of the compound In1-xMnxAs in which Mn atoms are substituted in indium-sites. We show by XMCD that In1-xMnxAs is ferromagnetic with a relatively high value of an average magnetic moment per Mn atom, exceeding 0.7mB at low temperatures and with an individual magnetic moment of about 2.4mB. The temperature dependence of the Mn magnetic moment follows the Brillouin function and it drops to zero at temperature of about 150K for measurements in an external magnetic field of 5T.