Atomic-scale analysis of interfaces in an all-oxide magnetic tunnel junction
Résumé
We use High Resolution Electron Microscopy (HRTEM) together with Electron Energy Loss Spectroscopy (EELS) to analyze the crystallography and the chemical configuration of interfaces in a state-of-the-art La2/3Sr1/3MnO3/SrTiO3/ La2/3Sr1/3MnO3 tunnel junction. EELS indicates that manganese ions keep their bulk valency up to the last atomic plane in contact with the insulator. Tunnel magnetoresistance however decreases with temperature faster than magnetisation in these samples. Quantitative HRTEM reveals some local departures from chemical abruptness at the interfaces, which could play a role in this decrease.
Mots clés
- Crystallography
- Electron energy loss spectroscopy
- High resolution electron microscopy
- Interfaces (materials)
- Lanthanum alloys
- Magnetic materials
- Magnetic variables measurement
- Magnetization
- Tunnel junctions
- Magnetic tunnel junction
- Atomic scale characterization
- Atomic scale analysis
- Transmission electron microscopy
- Strontium compounds
- Magnetoresistance