A perpendicular-anisotropy CoFeB-MgO magnetic tunnel junction

S. Ikeda, K. Miura, H. Yamamoto, K. Mizunuma, H. D. Gan, M. Endo, S. Kanai, J. Hayakawa, F. Matsukura, H. Ohno

Research output: Contribution to journalArticlepeer-review

2217 Citations (Scopus)

Abstract

Magnetic tunnel junctions (MTJs) with ferromagnetic electrodes possessing a perpendicular magnetic easy axis are of great interest as they have a potential for realizing next-generation high-density non-volatile memory and logic chips with high thermal stability and low critical current for current-induced magnetization switching. To attain perpendicular anisotropy, a number of material systems have been explored as electrodes, which include rare-earth/transition-metal alloys, L1 0 -ordered (Co, Fe)-Pt alloys and Co/(Pd, Pt) multilayers. However, none of them so far satisfy high thermal stability at reduced dimension, low-current current-induced magnetization switching and high tunnel magnetoresistance ratio all at the same time. Here, we use interfacial perpendicular anisotropy between the ferromagnetic electrodes and the tunnel barrier of the MTJ by employing the material combination of CoFeB-MgO, a system widely adopted to produce a giant tunnel magnetoresistance ratio in MTJs with in-plane anisotropy. This approach requires no material other than those used in conventional in-plane-anisotropy MTJs. The perpendicular MTJs consisting of Ta/CoFeB/MgO/CoFeB/Ta show a high tunnel magnetoresistance ratio, over 120%, high thermal stability at dimension as low as 40 nm diameter and a low switching current of 49μA.

Original languageEnglish
Pages (from-to)721-724
Number of pages4
JournalNature Materials
Volume9
Issue number9
DOIs
Publication statusPublished - 2010 Sep

ASJC Scopus subject areas

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

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