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Title: On the quality of molecular-beam epitaxy grown Fe/MgO and Co/MgO(001) interfaces

Abstract

We investigated in detail the structural, chemical, and magnetic properties of Fe at the interface with MgO. The samples were grown by molecular-beam epitaxy and analyzed by using reflection high-energy electron diffraction, scanning tunneling microscopy, Auger electron spectroscopy, x-ray photoemission spectroscopy (XPS), x-ray-absorption spectroscopy (XAS), and x-ray magnetic circular dichroism (XMCD) measurements. We discuss the presence or absence of C and O contaminants at the surface of the metallic film. We actually show that when growing the first Fe layer on the initial MgO substrate, a carbon contamination at the surface of the annealed Fe layer is observed leading to a C(2x2) surface structure. We propose a method to eliminate this carbon contamination and to get interfaces free of carbon. On the other hand, we observed that the reactivity of the Fe surface to oxygen contamination is greatly influenced by the presence of carbon or absence on the surface. The influence of oxygen adsorption at the Fe surface on the MgO growth will also be discussed. Concerning the hybridization between Fe or Co with MgO, XPS, and XAS-XMCD analyses clearly demonstrate that the charge transfer is weak, and that the magnetization at the interface is larger than in bulk (3{mu}{submore » B}/at for Fe). With such clean interfaces, reproducible magnetoresistance equal to 160% are obtained on Fe/MgO(3 nm)/Fe(001) 100x100 {mu}m{sup 2} tunnel junctions at room temperature in our laboratory. Finally, we show that pollution at the bottom Fe/MgO interface modify drastically spin-dependent tunneling properties.« less

Authors:
; ; ; ;  [1]
  1. Laboratoire de Physique des Materiaux, CNRS, University of H. Poincare, 54506 Vandoeuvre (France)
Publication Date:
OSTI Identifier:
20788113
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 99; Journal Issue: 8; Other Information: DOI: 10.1063/1.2165914; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION SPECTROSCOPY; AUGER ELECTRON SPECTROSCOPY; CARBON; CHARGE EXCHANGE; COBALT; ELECTRON DIFFRACTION; IRON; MAGNESIUM OXIDES; MAGNETIC CIRCULAR DICHROISM; MAGNETIC PROPERTIES; MAGNETORESISTANCE; MOLECULAR BEAM EPITAXY; OXYGEN; PHOTOEMISSION; SCANNING TUNNELING MICROSCOPY; SUPERCONDUCTING JUNCTIONS; TEMPERATURE RANGE 0273-0400 K; TUNNEL EFFECT; X-RAY PHOTOELECTRON SPECTROSCOPY; X-RAY SPECTROSCOPY

Citation Formats

Sicot, M, Andrieu, S, Tiusan, C, Montaigne, F, Bertran, F, and LURE-SOLEIL, BP48 Saint Aubin, 91192 Yves/Yvette. On the quality of molecular-beam epitaxy grown Fe/MgO and Co/MgO(001) interfaces. United States: N. p., 2006. Web. doi:10.1063/1.2165914.
Sicot, M, Andrieu, S, Tiusan, C, Montaigne, F, Bertran, F, & LURE-SOLEIL, BP48 Saint Aubin, 91192 Yves/Yvette. On the quality of molecular-beam epitaxy grown Fe/MgO and Co/MgO(001) interfaces. United States. https://doi.org/10.1063/1.2165914
Sicot, M, Andrieu, S, Tiusan, C, Montaigne, F, Bertran, F, and LURE-SOLEIL, BP48 Saint Aubin, 91192 Yves/Yvette. 2006. "On the quality of molecular-beam epitaxy grown Fe/MgO and Co/MgO(001) interfaces". United States. https://doi.org/10.1063/1.2165914.
@article{osti_20788113,
title = {On the quality of molecular-beam epitaxy grown Fe/MgO and Co/MgO(001) interfaces},
author = {Sicot, M and Andrieu, S and Tiusan, C and Montaigne, F and Bertran, F and LURE-SOLEIL, BP48 Saint Aubin, 91192 Yves/Yvette},
abstractNote = {We investigated in detail the structural, chemical, and magnetic properties of Fe at the interface with MgO. The samples were grown by molecular-beam epitaxy and analyzed by using reflection high-energy electron diffraction, scanning tunneling microscopy, Auger electron spectroscopy, x-ray photoemission spectroscopy (XPS), x-ray-absorption spectroscopy (XAS), and x-ray magnetic circular dichroism (XMCD) measurements. We discuss the presence or absence of C and O contaminants at the surface of the metallic film. We actually show that when growing the first Fe layer on the initial MgO substrate, a carbon contamination at the surface of the annealed Fe layer is observed leading to a C(2x2) surface structure. We propose a method to eliminate this carbon contamination and to get interfaces free of carbon. On the other hand, we observed that the reactivity of the Fe surface to oxygen contamination is greatly influenced by the presence of carbon or absence on the surface. The influence of oxygen adsorption at the Fe surface on the MgO growth will also be discussed. Concerning the hybridization between Fe or Co with MgO, XPS, and XAS-XMCD analyses clearly demonstrate that the charge transfer is weak, and that the magnetization at the interface is larger than in bulk (3{mu}{sub B}/at for Fe). With such clean interfaces, reproducible magnetoresistance equal to 160% are obtained on Fe/MgO(3 nm)/Fe(001) 100x100 {mu}m{sup 2} tunnel junctions at room temperature in our laboratory. Finally, we show that pollution at the bottom Fe/MgO interface modify drastically spin-dependent tunneling properties.},
doi = {10.1063/1.2165914},
url = {https://www.osti.gov/biblio/20788113}, journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 8,
volume = 99,
place = {United States},
year = {2006},
month = {4}
}