Observation of multiple transitions on permalloy ring by magnetic force microscopy

L. K. Lin, C. Y. Kuo, J. Y. Ou, C. C. Chang, C. R. Chang, Lance Horng, J. C. Wu

Research output: Contribution to journalConference articlepeer-review

2 Citations (Scopus)


We present a study of magnetization reversal on microstructured permalloy thin film rings using a magnetic force microscopy in the presence of external magnetic fields up to 540 Oe. Permalloy rings with fixed thickness/outside diameter of 23 nm/5 μm and inside diameter of 2.2 and 2.6μm, respectively, were fabricated by using standard electron beam lithography through a lift-off process. Four transitions during magnetization reversal were observed on the one with 2.2 μm inside diameter, in which the magnetization was evolved from onion to vortex-pair, vortex-pair to vortex, vortex to vortex-core, vortex-core to reverse onion state. The remanent state was flux closure vortex state. A similar magnetization evolution occurred on the one with 2.6 μm inside diameter except that the remanent state was vortex pair. The numerical simulation results using OOMMF showed good agreement with the experimental results. These multiple stable states during the magnetization reversal may provide an excellent opportunity for developing multibit storage cells.

Original languageEnglish
Pages (from-to)4360-4363
Number of pages4
JournalPhysica Status Solidi (C) Current Topics in Solid State Physics
Issue number12
Publication statusPublished - 2007 Dec 1
EventInternational Symposium on Advanced Magnetic Materials and Appilications, (ISAMMA 2007) - Jeju, Korea, Republic of
Duration: 2007 May 282007 Jun 1

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

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