Inverse TMR effect in Co0.9Fe0.1/ SrTiO3/La0.7MnO3 tunnel junctions

M. Sugiyama, H. Asano, M. Matsui, J. Hayakawa, S. Kokado, K. Itou, A. Sakuma, M. Ichimura

Research output: Contribution to journalConference article

Abstract

Magnetic tunnel junctions of Co0.9Fe0.1/SrTiO3 (STO)/ La0.7Sr0.3MnO3 (LSMO) with a spin-valve structure having an antiferromagnetic MnIr layer have been fabricated by sputtering. Junction magnetoresistance (MR) behavior and its dependence on the bias voltage are examined for junctions with epitaxial STO barrier formed under different sputtering conditions. Spin dependent transport measurements show that these junctions exhibit spin-valve type MR loops with an inverse (positive) MR of the ratio of 14-22% at 4.2 K. The inverse MR observed is asymmetric with respect to the bias voltage direction. Stoichiometric STO barrier, as characterized by Rutherford backscattering (RBS) analysis, is found to result in very large asymmetric bias dependence, while the junctions with nonstoichiometric STO barrier exhibit the symmetric bias dependence. Our results suggest that the nonstoichiometry of STO barrier modifies the electronic structures of electrode/barrier interfaces, and thereby reducing the asymmetry of bias voltage dependence of junction MR.

Original languageEnglish
Pages (from-to)29-34
Number of pages6
JournalMaterials Research Society Symposium - Proceedings
Volume690
Publication statusPublished - 2002 Jan 1
Externally publishedYes
EventSpintronics - Boston, MA, United States
Duration: 2001 Nov 262001 Nov 29

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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