CoFeB/MgO based perpendicular magnetic tunnel junctions with stepped structure for symmetrizing different retention times of "0" and "1" information

K. Miura, S. Ikeda, Michihiko Yamanouchi, H. Yamamoto, K. Mizunuma, H. D. Gan, J. Hayakawa, R. Koizumi, F. Matsukura, H. Ohno

Research output: Chapter in Book/Report/Conference proceedingConference contribution

23 Citations (Scopus)

Abstract

We investigated perpendicular magnetic tunnel junctions (p-MTJs) with a stepped structure for spin-transfer torque random access memory (SPRAM). In conventional p-MTJs, the retention time for storing "1" is shorter than that for storing "0," because of the mangetostatic energy difference between the two states caused by dipole interaction. To counter this, one had to develop materials with low magnetization. Here we show, by employing a stepped structure, that the retention time can be made equivalent regardless of the stored information ("0" or "1"), without resorting to the employed materials. This is because this structure reduces the dipole interlayer coupling between two ferromagnetic layers as the diameter difference of the free and reference layers of MTJ increases.

Original languageEnglish
Title of host publication2011 Symposium on VLSI Technology, VLSIT 2011 - Digest of Technical Papers
Pages214-215
Number of pages2
Publication statusPublished - 2011 Sep 16
Event2011 Symposium on VLSI Technology, VLSIT 2011 - Kyoto, Japan
Duration: 2011 Jun 142011 Jun 16

Publication series

NameDigest of Technical Papers - Symposium on VLSI Technology
ISSN (Print)0743-1562

Other

Other2011 Symposium on VLSI Technology, VLSIT 2011
CountryJapan
CityKyoto
Period11/6/1411/6/16

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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  • Cite this

    Miura, K., Ikeda, S., Yamanouchi, M., Yamamoto, H., Mizunuma, K., Gan, H. D., Hayakawa, J., Koizumi, R., Matsukura, F., & Ohno, H. (2011). CoFeB/MgO based perpendicular magnetic tunnel junctions with stepped structure for symmetrizing different retention times of "0" and "1" information. In 2011 Symposium on VLSI Technology, VLSIT 2011 - Digest of Technical Papers (pp. 214-215). [5984638] (Digest of Technical Papers - Symposium on VLSI Technology).