Abstract
An electron-microscopy-based technique of electron-energy-loss spectroscopy (EELS) has been used to characterize electronic and magnetic properties of ultrathin Fe films grown on GaAs(100) surface, as a function of the film thickness. Large-area electron transparent membranes for microscopic analysis are prepared by ion-beam thinning or chemical etching from the substrate side, and the top surface of the ultrathin Fe film is protected by a thin Cr layer. Analysis of the Fe 2p, Cr 2p, and O 1s absorption spectra confirms that only the Cr layer is oxidized. The local magnetic moments of the ultrathin Fe films are deduced from the ''white line'' branching ratio in the Fe 2p absorption spectra. For Fe films as thin as 150 angstrom, the magnetic moment is not different from that found in bulk alpha-Fe. For a 70-angstrom Fe film, the local magnetic moment is enhanced although the average magnetization is reduced. As doping is suspected to be the cause for the departure from bulk alpha-Fe properties. In the case where the 50-angstrom film is polycrystalline and discontinuous, spatially resolved EELS has been used to distinguish small island clusters from large crystalline particles. The large particles are alpha-Fe crystallites and the islands are probably also heavily affected by As doping.
| Original language | English |
|---|---|
| Pages (from-to) | 6501-6503 |
| Number of pages | 3 |
| Journal | Journal of Applied Physics |
| Volume | 75 |
| Issue number | 10 |
| Publication status | Published - 15 May 1994 |
Keywords
- 3D TRANSITION-METALS
- MAGNETIZATION
- INTERFACE
- EPITAXY
- GAAS