Bethanie J. Hills Stadler

Assistant Professor

Electrical and Computer Engineering

University of Minnesota



“Artificial Cilia: Biologically Inspired Acoustic Sensors”

Tiny hair-like sensors, or cilia, play a very important role in detection for many biological species, including humans.  Realizing this, our research took inspiration from the packaging and transduction processes of the inner ear's cochlea and cilia to design acoustic sensors.  Specifically, this work uses nanowires of magnetostrictive materials as hair-like sensors of ultrasonic and acoustic signals.  Nanowires of the Fe-Ga alloy system, Fe1-xGax (0.1?x?0.25 at. %), are being fabricated using electrochemical deposition into nanoporous anodic alumina. Fe-Ga alloys are magnetically soft, mechanically robust, ductile, and have large magnetostriction. High aspect ratio nanowires with varying diameters and lengths are being fabricated in arrays and are collectively and individually characterized using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The magnetic response of the arrays is also being measured using vibrating sample magnetometry (VSM). Co/Cu multilayered nanowires are being studied as a future method of achieving detection of the cilia with high resolution.  Varying the thicknesses of the multilayers also enables interesting studies of the various magnetic anisotropies that exist in these nanowires.  Applications of these nanowire cilia include sonar arrays, underwater cameras, and medical devices.