Interfacial mixing in double-barrier magnetic tunnel junctions with amorphous NiFeSiB layers

B. S. Chun, S. P. Ko, J. Y. Hwang, J. R. Rhee, T. W. Kim, Y. K. Kim

Research output: Contribution to journalArticle

Abstract

Double-barrier magnetic tunnel junctions (DMTJs) comprising Ta 45/Ru 9.5/IrMn 10/CoFe 7/AlOx/free layer (CoFe 4/NiFeSiB 2/CoFe 4, CoFe 10, or NiFeSiB 10)/AlOx/CoFe 7/IrMn 10/Ru 60 (nm) have been examined with an emphasis given on understanding the interfacial mixing effects. The DMTJ, consisted of NiFeSiB, shows low switching field and low bias voltage dependence because the amorphous NiFeSiB has lower MS (=800 emu/cm3) and offers smoother interfaces than polycrystalline CoFe. An interesting feature observed in the CoFe/NiFeSiB/CoFe sandwich free layered DMTJ is the presence of a wavy MR transfer curve at high-resistance region. Because the polycrystalline CoFe usually grows into a columnar structure, diamagnetic CoSi, paramagnetic FeSi, and/or diamagnetic CoB might have been formed during the sputter-deposition process. By employing electron energy loss spectrometry (EELS) and Auger electron spectroscopy (AES), we were able to confirm that Si and B atoms were arranged evenly in the top and bottom portions of AlOx/CoFe interfaces. This means that the interfacial mixing resulted in a distorted magnetization reversal process.

Original languageEnglish
Pages (from-to)e638-e640
JournalJournal of Magnetism and Magnetic Materials
Volume310
Issue number2 SUPPL. PART 3
DOIs
Publication statusPublished - 2007 Mar

Keywords

  • Intermixing
  • Magnetic tunnel junction
  • NiFeSiB

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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