Dresden 2006 – scientific programme
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MA: Magnetismus
MA 20: Poster: Films(1-36) Transp(37-56) Ex.Bias(57-67) Spindyn(68-80) Micromag(81-95) Particle(96-109) Imag.+Surface(110-113) Spinelectr(114-122) Theory+Micromag(123-131) Spinstr+Aniso(132-142) MagMat(143-156) Meas(157,158) MolMag+Kondo(159-162) Postdead(163-)
MA 20.93: Poster
Tuesday, March 28, 2006, 15:15–19:15, P1
Magnetization reversal of individual permalloy particles by coherent rotation — •Joachim Stahl, Werner Wegscheider, and Dieter Weiss — University of Regensburg, Institute for Experimental and Applied Physics, D-93040 Regnsburg
Nanostructured ferromagnetic disks show a transition of the remanent magnetization configuration from a vortex to a single domain state with decreasing dimensions. Here, the magnetization reversal of individual permalloy particles entering this single domain range is studied by means of micro-Hall magnetometry. In contrast to integral methods which are averaging over a large number of nanomagnets [1] the results obtained here are not affected by broadening of the switching field.
By reducing the thickness to diameter ratio the single domain limit can be entered. For studying this regime disks with different diameter and thickness were fabricated. Therefore the Hall signal UH caused by the stray field of one single disk during magnetization reversal in an external magnetic in-plane field Hext is measured. For example a disk with a diameter of 100 nm and a thickness of 10 nm was fabricated on a sub-µm Hall sensor. As in the experiment simulations with LLG [2] also show an abrupt switching of the disk’s magnetization without indicating any curling effects. Hence micro-Hall magnetometry proves to be a simple tool to investigate individual true single domain particles.
[1] R. P. Cowburn, et al., Phys. Rev. Lett. 83, 1042 (1999)
[2] LLG Micromagnetics Simulator by M. Scheinfein, see
http://llgmicro.home.mindspring.com/