Issue Eur. Phys. J. Appl. Phys. Volume 24, Number 3, December 2003 Page(s) 215 - 221 Section Plasmas, Discharges and Processes DOI 10.1051/epjap:2003071 Published online 03 October 2003

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

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

J.-L. Maurice¹, F. Pailloux¹, D. Imhoff², N. Bonnet³, L. Samet², A. Barthélémy¹, J.-P. Contour¹, C. Colliex² and A. Fert<sup>1

1</sup>  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

jean-luc.maurice@thalesgroup.com

(Received: 18 February 2003 / Received in final form: 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 _1/3MnO ₃/SrTiO ₃/La _2/3Sr _1/3MnO ₃ 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.

PACS
75.47.Lx - Manganites.
75.70.Cn - Magnetic properties of interfaces (multilayers, superlattices, heterostructures).
68.37.Lp - Transmission electron microscopy (TEM) (including STEM, HRTEM, etc.).

© EDP Sciences 2003

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