Project A7 - Electrically Modulated Magnetoelectric Sensors
Research of the first funding period has shown that electrically modulated mesoscopic ME composites, targeting especially high frequency mechanical resonances, far higher than flexural modes, lead to dramatically enhanced converse ME effect. This is observed by vibrometry as well as in-situ MOKE studies. Exciting high frequency resonances of an ME composite immersed in an inductor while matching the inductive self-resonance to the mechanical resonance provides intrinsic amplification towards the converse ME effect, thus forming an overall resonant circuit. This resonant circuit proves very sensitive to external magnetic fields: 215 pT/Hz1/2 are obtained at DC, reaching 73 pT/Hz1/2 at 10 Hz. The use of magnetostrictive (MS) materials involving sophisticated exchange bias leads to even lower detection limits of 30 pT/Hz1/2 at 10 Hz. As high frequency resonances typically undergo less damping than flexural modes, high mechanical quality factors are readily reached at ambient pressure. The combination of high frequencies and high mechanical quality factors leads to increased available sensing bandwidth on the order of several hundred Hertz, suitable to biomagnetic as well as deep brain stimulation (DBS) application requirements.
The work of the second funding period will be focused on deriving a comprehensive signal-to-noise model of the electrically modulated ME sensor. The work on the model will be performed in close collaboration with modelling and characterization (projects A8, A10, and B1). More detailed objectives are to investigate the influence of
- the homogeneity of the resonance mode,
- the nature of the magnetization reversal processes,
- the orientation of the easy axis, and
- the resonance frequency of the U mode on the signal and the noise of these sensors.
Finally, the influence of the size of the sensor on its overall performance will be investigated, as many biomagnetic applications require a high spatial resolution.
Involved Researchers
Person | Role | |
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Prof. Dr. Eckhard Quandt Materials Science Inorganic Functional Materials |
Project lead | |
Dr. Felix Schlichting Materials Science Multicomponent Materials |
Doctoral researcher |
Role within the Collaborative Research Centre
The Collaborative Research Centre 1261 “Magnetoelectric Sensors: From Composite Materials to Biomagnetic Diagnostics” spans a wide range of projects: from materials research to sensor concepts to signal processing and finally to applications. Because this project deals with one of the sensor concepts, it is fully integrated within this research chain and we will have intense collaborations with materials research, sensor systems, and especially with the transfer project. Specifically, this sensor concept reaches all secondary requirements demanded by applications such as high bandwidth, acoustic immunity, and no required bias field, which makes it particularly relevant to T1.
Collaborations | |
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A1 (Magnetostrictive Multilayers for Magnetoelectric Sensors) | Exchange biased multilayers. |
A6 (Microstructure and Structural Change of Magnetoelectric and Piezotronic Sensors) | Microstructural characterization of deposited piezoelectric layers. |
A8 (Modelling of Magnetoelectric Sensors) | Modelling of the sensors. |
A10 (Magnetic Noise of Magnetoelectric Sensors) | Modelling of the noise, in operando MOKE measurements. |
B1 (Sensor Noise Performance and Analogue System Design) | Analog electronics, noise floor characterization, LOD measurements. |
B2 (Digital Signal Processing) | If branching in WP6 occurs, multichannel acquisition and digital signal processing. |
T1 (Transfer project – Individualized Deep Brain Stimulation) | Support by using electrically modulated ME sensors for DBS measurements. |
Z1 (MEMS Magnetoelectric Sensor Fabrication) | Sensor miniaturization and fabrication, vibrometry measurements. |
Z2 (Magnetoelectric Sensor Characterization) | Instrumentation and sensor characterization. |
Project-related Publications
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