Fabrication and properties of heteroepitaxial magnetite (Fe3O4) tunnel junctions

X. W. Li*, A. Gupta, Gang Xiao, W. Qian, V. P. Dravid

*Corresponding author for this work

Research output: Contribution to journalArticle

170 Scopus citations

Abstract

Micron-size magnetic tunnel junctions consisting of ferromagnetic Fe3O4 electrodes, with MgO as a barrier layer, have been fabricated on (100) MgO substrates. Reflection high-energy electron diffraction and transmission electron microscopy studies reveal that the Fe3O4/MgO/Fe3O4 trilayers grown by pulsed laser deposition are heteroepitaxial with abrupt interfaces. To achieve different coercivities for the top and bottom Fe3O4 layers, the trilayers are grown on MgO substrates with a CoCr2O4 buffer layer. The junctions exhibit nonlinear current-voltage characteristics and changes in junction resistance with applied field corresponding to the coercivities of the two magnetic layers. However, the observed magnetoresistance (∼0.5% at 300 K, ∼1.5% at 150 K) is much lower than would be expected for a highly spin-polarized system. Possible reasons for the reduced magnetoresistance are discussed.

Original languageEnglish (US)
Pages (from-to)3282-3284
Number of pages3
JournalApplied Physics Letters
Volume73
Issue number22
DOIs
StatePublished - Dec 1 1998

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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