Abstract
Large area square arrays of circular cobalt dots, nominally 100 nm in diameter and 20 nm in thickness, were patterned using interference lithography. Magnetic remanent states were measured using off-axis electron holography in the transmission electron microscope (TEM). The results show that the dots are mostly single domain, although vortex states and multidomain configurations are occasionally observed. Significant magnetic interactions between adjacent dots result in variations in their magnetization direction away from the direction of the applied field. The suitability of such dots for data storage applications is discussed. Quantitative magnetic phase measurements were also obtained by applying the transport of intensity equation to images acquired using the Fresnel mode of Lorentz microscopy in the TEM. The consistency between the electron holography and transport of intensity equation (TIE) results is assessed.
Original language | English (US) |
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Article number | 053909 |
Journal | Journal of Applied Physics |
Volume | 98 |
Issue number | 5 |
DOIs | |
State | Published - Sep 1 2005 |
Funding
We thank R. C. Doole for help with Lorentz microscopy, D. Kirk for help with EELS and Professor M. R. McCartney for help with the electron holography, and Professor G. W. Smith and Professor D. J. Fray for the provision of laboratory space. One of the authors (T.J.B.) acknowledges funding from the EPSRC. Another author (C.A.R.) acknowledges the NSF for financial support and M. Farhoud for sample fabrication. Another author (R.E.D.) is grateful to the Royal Society for financial support. We acknowledge the use of facilities at the John M. Cowley Center for High-Resolution Electron Microscopy at Arizona State University, USA.
ASJC Scopus subject areas
- General Physics and Astronomy