Probing tunnel barrier shape and its effects on inversed tunneling magnetoresistance at high bias

Wen Ting Sheng, W. G. Wang, X. H. Xiang, F. Shen, L. I. Fei-Fei, T. Zhu, Z. Zhang, Zheng Zhong Li, D. U. Jun, A. N. Hu, John Q. Xiao

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


We have used an electron holography (EH) technique to directly probe the potential profile of tunnel barriers in magnetic tunnel junctions (MTJs). Barriers with under-, optimum-, or over-oxidized condition have been investigated. One important finding is that there is always slight oxidation of the top electrode because of film morphology. Sharp interfaces can be achieved in the bottom interface of optimally oxidized barrier or both interfaces in MTJs with under-oxidized barriers. We also demonstrate, theoretically and experimentally, how barrier shape affects the bias dependence and, in low barrier height case, result in inversed tunneling magnetoresistance (TMR) at high bias. The mechanism is very different from that responsible for inversed TMR in all biases. The finding leads to the possibilities of achieving better signals at high bias in real applications.

Original languageEnglish (US)
Pages (from-to)1274-1279
Number of pages6
JournalJournal of Electronic Materials
Issue number11
StatePublished - Nov 2004


  • Electron hologram
  • Inversed tunnel magnetoresistance (TMR)
  • Magnetic tunnel junction (MTJ)
  • Zro

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry


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