Volker Röbisch

TL;DR: In this paper, a comparison between magnetoelectric composite sensors based on AlN and FeCoSiB with and without exchange bias coupling is presented. All layer stacks were fabricated by thin film deposition on Si substrates.

TL;DR: In this article, the authors demonstrate the feasibility of an electric frequency conversion of a magnetoelectric sensor which would overcome the drawbacks of magnetic frequency conversion, and a limit of detection in the low nT/Hz 1/2 range was shown for signals of low frequency.

Abstract: Composite magnetoelectrics implemented as thin film heterostructures are discussed in view of their applicability as highly sensitive magnetic field sensors. Here, either PZT or AlN served as piezoelectric component. The magnetostrictive phase consisted of layer systems based on FeCo or (Fe90Co10)78Si12B10. All functional layers were deposited with thicknesses of a few micrometers on Si cantilever structures with typical lateral dimensions of 25 mm by 2.2 mm. Magnetoelectric coefficients as large as 6900 V/cm Oe and a limit of detection as low as 1 pT/(Hz)1/2 were measured. Currently, the best result demonstrates a detection limit of 500 fT/(Hz)1/2 at 958 Hz frequency using a set of two sensors for external noise suppression. A frequency conversion technique is proposed to broaden the applicability of resonant magnetoelectric sensors to a wider frequency range. Finally, the achieved sensor performance is evaluated with regard to typical magnetic field amplitudes in medical applications.

TL;DR: In this paper, an antiparallel (AP) exchange biasing scheme was used to suppress magnetic domain (MD) activity in magnetoelectric (ME) thin film composite sensors, which enabled the detection of picotesla magnetic fields.

TL;DR: In this article, a magnetostrictive multilayer of 3'×'3'nm Fe-Co-Si-B with a maximum voltage coefficient αME ≈'430'V/cm Oe was found.