Magnetic tunnel junctions on magnetic shield smoothed by gas cluster ion beam

J. J. Sun, K. Shimazawa, N. Kasahara, K. Sato, T. Kagami, S. Saruki, S. Araki, M. Matsuzaki

Research output: Contribution to journalConference articlepeer-review

50 Citations (Scopus)

Abstract

In this work, a technique, gas cluster ion beam (GCIB), was introduced to smooth the bottom NiFe magnetic shield for magnetic tunnel junction (MTJ) read heads. The GCIB treatment can bring the surface roughness of the shield from 15 to 20 Å to around 5 Å, and the most of scratch marks can be removed. The efficiency of the GCIB process is dependent on the initial surface morphology. The MTJs grown on the magnetic shield smoothed by the GCIB show that the resistance area product RA is increased from 60 to ∼100 Ω μm2 with the GCIB dose up to 1 × 1016 ions/cm2, arising from a smooth insulating layer, meanwhile, the tunneling magnetoresistance (TMR) is almost constant or slightly decreases. This GCIB process can also improve breakdown voltage (approximately 0.019 V per 1015 ions/cm2) of the MTJs, and slightly increase the ferromagnetic coupling mainly due to the change of the surface morphology. Using this technology, an RA as low as 3.5-6.5 Ω μm2 together with a TMR of 14%-18% can be obtained for MTJs grown on the GCIB treated NiFe magnetic shield.

Original languageEnglish
Pages (from-to)6653-6655
Number of pages3
JournalJournal of Applied Physics
Volume89
Issue number11 II
DOIs
Publication statusPublished - 2001 Jun 1
Externally publishedYes
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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