Ferromagnetism in manganese doped indium antimonide semiconductor thin films grown by metalorganic vapor phase epitaxy.

摘要

The InMnSb magnetic alloy system was developed for its potential application as a room temperature spintronic device material. Epitaxial In1-xMn xSb films were deposited using atmospheric pressure metal-organic vapor phase epitaxy on InSb(001) and InAs(001) substrates. Films are nominally single phase and epitaxial as determined by x-ray diffraction. The lattice constant of the film decreased with increasing Mn concentration. The films are compositionally homogenous on the nanometer size scale as determined by high resolution transmission electron microscopy measurements.;Extended x-ray absorption fine structure analysis indicates that the Mn substitutes for In with tetrahedral site-symmetry. InMnSb film shows local order consisting of clusters of five manganese atoms where the average distance between two clusters is 2.1 nm. X-ray absorption near edge spectroscopy and x-ray absorption spectroscopy studies indicate a highly localized Mn 2+ ion with a 3d5 ground state electronic configuration. Room temperature x-ray magnetic circular dichroism measurements indicate a net spin polarization of the carriers.;The films exhibit room temperature ferromagnetism as determined by superconducting quantum interference device magnetometry. Reversible field cooled and zero field cooled magnetization curves indicate the homogenous nature of ferromagnetism in the films. The Curie temperature of (In,Mn)Sb thin films is 580 K. Films are p-type semiconductors, with carrier concentration ranging from 5x1018 cm-3 - 2.3x1020 cm -3. Room temperature anomalous Hall effect is observed supporting a carrier-mediated ferromagnetic mechanism.