A novel SPRAM (SPin-transfer torque RAM) with a synthetic ferrimagnetic free layer for higher immunity to read disturbance and reducing write-current dispersion

K. Miura, T. Kawahara, R. Takemura, J. Hayakawa, Shoji Ikeda, R. Sasaki, H. Takahashi, H. Matsuoka, Hideo Ohno

Research output: Contribution to journalConference articlepeer-review

28 Citations (Scopus)

Abstract

A novel SPRAM (SPin-transfer torque RAM) consisting of MgO-barrier-based magnetic tunnel junctions (MTJs) with a synthetic ferrimagnetic (SyF) structure in a free layer was demonstrated for both higher immunity to read disturbance and a sufficient margin between the read and write currents. Since magnetization of the free layer becomes stable against thermal fluctuation with increasing thermal-stability factor E/kBT, the SyF free layer of the MTJs realized a magnetic information retention of over 10 years due to its high E/kBT of 67. Furthermore, it was found that the SyF free layer has an advantage of reducing dispersion of write-current density Jc, which is necessary for securing an adequate margin between the read and write currents.

Original languageEnglish
Article number4339706
Pages (from-to)234-235
Number of pages2
JournalDigest of Technical Papers - Symposium on VLSI Technology
DOIs
Publication statusPublished - 2007 Dec 1
Event2007 Symposium on VLSI Technology, VLSIT 2007 - Kyoto, Japan
Duration: 2007 Jun 122007 Jun 14

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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