Eur. Phys. J. Appl. Phys. 24, 215-221 (2003)
https://doi.org/10.1051/epjap:2003071

Atomic-scale analysis of interfaces in an all-oxide magnetic tunnel junction

¹ Unité Mixte de Physique CNRS/Thales, 91404 Orsay, France
² Laboratoire de Physique des Solides, Université Paris-Sud, 91405 Orsay, France
³ UMR-S INSERM 514 and LERI, University of Reims, 51092 Reims Cedex, France

Corresponding author: jean-luc.maurice@thalesgroup.com

Received: 18 February 2003
Revised: 22 May 2003
Accepted: 11 July 2003
Published online: 3 October 2003

Abstract

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 La_2/3Sr_1/3MnO₃/SrTiO₃/La_2/3Sr_1/3MnO₃ 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.