Regensburg 2010 – scientific programme

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MA: Fachverband Magnetismus

MA 33: Poster II

MA 33.15: Poster

Friday, March 26, 2010, 11:00–14:00, Poster B1

Noise characterization of a linearized submicron MTJ sensor array with CoFeB and Heusler alloy free-layers — •Peter Hedwig, Camelia Albon, Alexander Weddemann, and Andreas Hütten — Universität Bielefeld, Fakultät für Physik, Universitätsstr. 25, 33615 Bielefeld

Recently a lot of effort is put into the detection of magnetic particles and beads based on magnetoresistive elements, employing Spin-Valves, GMR and TMR elements. Most of these have a large size of several micrometers and are therefore of limited spatial resolution.

In our work, we present a submicron sensor-array based on linearized CoFeB/MgO/CoFeB-MTJs with a very high spatial resolution of below xy µm for the dynamic detection of magnetic markers, further extending the scope of possible applications as a “magnetic microscope”.

The sensor-array is characterized by static bead measurements and also by measuring its noise performance. According theoretical calculations regarding the sensor-bead-interaction and the limits of detection under consideration of the signal-to-noise-ratio were carried out. Additionally first results for Heusler-Alloys as the free-layer material will be presented, indicating an improved noise performance over the standard CoFeB free-layer.