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Publications in Scientific Journals:

J. Fidler, T. Schrefl, V. Tsiantos, W. Scholz, D. Süss:
"Micromagnetic simulation of the magnetic switching behaviour of mesoscopic and nanoscopic structures";
Computational Materials Science, 24 (2002), 163 - 174.



English abstract:
Micromagnetic simulation of the magnetic switching behaviour of mesoscopic and nanoscopic structures

J. Fidler [Corresponding Author Contact Information] , [E-mail The Corresponding Author] , T. Schrefl, V. D. Tsiantos, W. Scholz and D. Suess

Institute of Applied and Technical Physics, Vienna University of Technology, Wiedner Haupstrasse 8-10/137, A-1040 Wien, Austria

Available online 7 March 2002.
Abstract

Magnetic switching of small particles, thin film elements and nano-wires becomes increasingly important in magnetic storage and magneto-electronic devices. The magnetisation reversal processes are studied using a three-dimensional hybrid finite element/boundary element micromagnetic model. Transient magnetization states during switching are investigated numerically in thin Ni80Fe20 and Co nano-elements of square (100×100 nm2), rectangular (100×300 nm2 ) and circular (100 nm diameter) shapes with a thickness of 20 nm. Switching dynamics are calculated for external fields applied instantaneously and for rotational fields with field strengths in the order of the static critical field (Hext=0.02?0.32Js/ [small mu, Greek] 0 ). Reversal in the unidirectional field proceeds by the nucleation and propagation of end domains toward the centre of the particle. It is found that the switching time strongly depends on the Gilbert damping parameter [small alpha, Greek] . Small values of [small alpha, Greek] ( [less-than-or-equals, slant] 0.1) lead to shorter switching times at small field strength values, whereas for Hext=0.6?1.0Js/ [small mu, Greek] 0 minimum switching times occur for large damping value [small alpha, Greek] =1.0. Materials with uniaxial magneto-crystalline anisotropy, such as Co, require larger field strengths, but exhibit shorter switching times. Reversal in rotational fields involves inhomogeneous rotation of the end domains toward the rotational field direction. Depending on the damping parameter fast switching times ( [less-than-or-equals, slant] 0.1 ns) are obtained by increasing the field strength to Hext=0.5Js/ [small mu, Greek] 0 . Taking into account thermal fluctuations the reversal mechanisms of Co nano-wires were studied, and values for the activation volume and for the domain wall velocity were derived.


Electronic version of the publication:
http://www.elsevier.com/locate/commatsci


Created from the Publication Database of the Vienna University of Technology.