Atomic and Electronic Structure of the BaTiO3/Fe Interface in Multiferroic Tunnel Junctions

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• 作者：Laura Bocher ; Alexandre Gloter ; Arnaud Crassous ; Vincent Garcia ; Katia March ; Alberto Zobelli ; Sergio Valencia ; Sha茂ma Enouz-Vedrenne ; Xavier Moya ; Neil D. Marthur ; Cyrile Deranlot ; St茅phane Fusil ; Karim Bouzehouane ; Manuel Bibes ; Agn猫s Barth茅l茅my ; Christian Colliex ; Odile St茅phan
• 刊名：Nano Letters
• 出版年：2012
• 出版时间：January 11, 2012
• 年：2012
• 卷：12
• 期：1
• 页码：376-382
• 全文大小：442K
• 年卷期：v.12,no.1(January 11, 2012)
• ISSN：1530-6992

文摘

Artificial multiferroic tunnel junctions combining a ferroelectric tunnel barrier of BaTiO₃ with magnetic electrodes display a tunnel magnetoresistance whose intensity can be controlled by the ferroelectric polarization of the barrier. This effect, called tunnel electromagnetoresistance (TEMR), and the corollary magnetoelectric coupling mechanisms at the BaTiO₃/Fe interface were recently reported through macroscopic techniques. Here, we use advanced spectromicroscopy techniques by means of aberration-corrected scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS) to probe locally the nanoscale structural and electronic modifications at the ferroelectric/ferromagnetic interface. Atomically resolved real-space spectroscopic techniques reveal the presence of a single FeO layer between BaTiO₃ and Fe. Based on this accurate description of the studied interface, we propose an atomistic model of the ferroelectric/ferromagnetic interface further validated by comparing experimental and simulated STEM images with atomic resolution. Density functional theory calculations allow us to interpret the electronic and magnetic properties of these interfaces and to understand better their key role in the physics of multiferroics nanostructures.

Keywords:

Atomically resolved EELS; aberration-corrected STEM; multiferroic nanojunctions; ab initio calculations