Dresden 2014 – scientific programme
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DS: Fachverband Dünne Schichten
DS 11: Focus Session: Sensoric Micro and Nano-systems I
DS 11.3: Talk
Tuesday, April 1, 2014, 10:15–10:30, CHE 89
Integrated MEMS magnetic field sensor based on ΔE-effect — •Sebastian Zabel1, Robert Jahns2, Stephan Marauska3, Björn Gojdka2, Bernhard Wagner3, Rainhard Knöchel1, Rainer Adelung4, and Franz Faupel2 — 1Institute for Materials Science, Multicomponent Materials, Kiel University, Kiel, Germany — 2Institute of Electrical and Information Engineering , Kiel University — 3Fraunhofer Institute for Silicon Technology ISIT, Itzehoe, Germany — 4Institute for Materials Science, Functional Nanomaterials, Kiel University
We present an integrated MEMS magnetic field sensor based on ΔE-effect, which extends our previous approach [Gojdka et al., Appl. Phys. Lett. 99, 223502 (2011); Nature 480, 155 (2011)]. The ΔE-effect describes a change of elastic modulus in magnetostictive materials upon application of a magnetic field. The change of elastic modulus can be measured by the change of resonance frequency of a one side clamped cantilever. The 0.2 x 1 mm SiO2 cantilever is 650 nm thick and coated with a 500 nm thick piezoelectric AlN layer on the bottom and a 2 um thick magnetostrictive FeCoSiB amorphous film on top. The piezoelectric layer is used for excitation of the first resonant bending mode as well as the readout of amplitude and phase. The sensor resonates at 6700 Hz and is encapsulated in a vacuum packing to reduce damping. Using amplitude modulation it is possible to detect small signals of 10 nT at 10 Hz. In order to use the maximal ΔE-effect a bias field of around 1.5 mT has to be applied. The advantage of the sensor concept is the possibility to measure in a broad frequency range down to DC.