SPring-8, the large synchrotron radiation facility

Date&Time: 16:00-17:00, 18 May, 2004

Speaker: Dr. Jun Okabayashi
Affiliation: Department of Applied Chemistry, The University of Tokyo

Abstract
　　Successful combination of magnetic properties of Mn compounds with semiconducting properties of III-V compound semiconductors has lead to the creation of a new class of materials called diluted magnetic semiconductors such as Ga1-xMnxAs and In1-xMnxAs. However, the Curie temperature of Ga1-xMnxAs has not exceeded 150 K so far, because of the solubility limit of Mn in GaAs. To overcome this issue, we have focused on the high-concentration limit of Ga1-xMnxAs, that is MnAs with zinc-blende-type crystalline structure, which is realized in the nanostructures. In this talk, first, I report on the fabrication of the MnAs nanostructures such as (i) Mn delta-doping, (ii) MnAs clusters in GaAs matrix, and (iii) MnAs dots on sulfur-passivated GaAs surface. Second, I report on the spectroscopic characterization using in-situ photoemission spectroscopy, x-ray absorption spectroscopy, and x-ray magnetic circular dichroism.