Magnetic Nanoparticles for Novel Granular Spintronic Devices

A. Regtmeier[1], A. Weddemann[2], I. Ennen[3], and A. Hütten[1]
[1]Dept. of Physics, Thin Films and Physics of Nanostructures, Bielefeld University, Bielefeld, Germany
[2]Dept. of Elect. Eng. and Comp. Science, Lab. for Electromagnetic and Electronic Syst., MIT, Cambridge, MA
[3]Institute of Solid State Physics, Vienna University of Technology, Vienna, Austria
Published in 2011

Superparamagnetic nanoparticles have a wide range of applications in modern electric devices. Recent developments have identi fied them as components for a new type of magnetoresistance sensor. We propose a model for the numeric evaluation of the sensor properties. Based on the solutions of the Landau-Lifshitz-Gilbert equation for a set of homogeneously magnetized spheres arranged in highly symmetric monolayers, we analyze how di fferent device properties may be adjusted to speci fic demands by modi fications of the microstructure.

We characterize sensor properties and identify di fferent measurement regimes which correspond to speci fic dominating energy contributions. In particular, we find a novel measuring mode where increased field sensitivity is bought at the cost of an inherent device noise.

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