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Magnetization Reversal and Configurational Anisotropy of Dense Permalloy Dot Arrays
journal contributionposted on 2012-03-15, 00:00 authored by Xiaobin Zhu, P. Grütter, V. Metlushko, B. Ilic
Electron beam patterned permalloy circular dots of 700 nm diameter with small separations were studied by magnetic force microscopy (MFM) in the presence of an in situ magnetic field. Images in the demagnetized state show that the dot is in a vortex state with a vortex core (singularity) in the center. Local hysteresis loops, measured by cantilever frequency shift in an external field, indicate that the magnetization reversal of individual disks is a vortex nucleation and annihilation process. By carefully doing MFM, nucleation and annihilation fields without MFM tip stray field distortions are obtained. Configurational anisotropy originated from magnetostatic coupling is found through hysteresis loops.
This work at McGill was supported by grants from NSERC of Canada and FCAR of Québec. This work at UIC was supported by the U.S. NSF Grant No. ECS-0202780 (V.M.).
Publisher Statement© 2011 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Zhu, X., Grütter, P., Metlushko, V., & Ilic, B. 2002. Magnetization reversal and configurational anisotropy of dense permalloy dot arrays. Applied Physics Letters, 80(25): 4789-4791. and may be found at http://apl.aip. DOI: 10.1063/1.1489720
PublisherAmerican Institute of Physics