Enhancement of exchange bias in Mn-Ir/Co-Fe based spin valves with an ultrathin Cu underlayer and in situ Mn-Ir surface modification

Kojiro Yagami, Masakiyo Tsunoda, Migaku Takahashi

Research output: Contribution to journalConference articlepeer-review

21 Citations (Scopus)

Abstract

Enhancement of exchange bias induced at the interface of the antiferromagnetic (AF)/ferromagnetic (F) layers was studied using the bottom "spin-valve films" (SVs) with the Mn-Ir/Co-Fe exchange coupled films. Exchange bias increased using an ultrathin Cu underlayer. Meanwhile, both exchange bias field, Hex, and blocking temperature, TB, increased intensively by heating specimens after depositing Mn-Ir film in a high vacuum. These two enhancement effects worked in an additive. As a result, an unidirectional anisotropy constant. JK, of 0.39 erg/cm2 (Hex of 1.3 kOe) and TB of ∼325°C were obtained for the bottom SVs with a total thickness of 233 Å including an AF layer of 68 Å Mn74Ir26 and a pinned layer of 20 Å Co90Fe10, where the SVs were field annealed at 320°C. A microstructural analysis using x-ray diffraction revealed that Hex did not depend on the diffraction intensity from Mn-Ir (111) for the SVs with various underlayers, and no remarkable changes occurred in the microstructure of the SVs with the heating treatment in vacuum. Therefore, the enhancement effects might result from some changes in the microstructure and/or the morphology of the interface of AF/F layers.

Original languageEnglish
Pages (from-to)6609-6611
Number of pages3
JournalJournal of Applied Physics
Volume89
Issue number11 II
DOIs
Publication statusPublished - 2001 Jun 1
Event8th Joint Magnetism and Magnetic Materials-Intermag Conference - San Antonio, TX, United States
Duration: 2001 Jan 72001 Jan 11

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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