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Michael Zach
Materials Science Division
Appointment: 04/2004 - 07/2006
Supervisor: Wai-Kwong Kwok
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General Information
- Glenn Seaborg Named Scholar
- Assistant Professor of Chemistry
- University of Wisconsin at Stevens Point
- 2001 Fourth Avenue
- Science D Wing, D0145
- Stevens Point , WI 54481-3897
- Phone: (715) 544 - 0286
- Email: mzach@uwsp.edu
- http://chemdept-nmr.uwsp.edu/~mzach/
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ANL Research Highlights
1.
Hydrogen is being viewed as a future energy transfer medium with intense interest because of its potential environmental benefits. As the importance of hydrogen to many industries increases, there is a greater need for high performance sensors to monitor hydrogen safety. Currently, all commercial hydrogen sensors have response times of 10 seconds or more with limited conditions for sensing hydrogen. The only other rapid sensor (with response times under 100 milliseconds) is based on electrochemically grown nanowires that rely on tedious oneat- a-time, hand fabrication methods. Our sensors represent a great advance over these nanowire based sensors. The fabrication of 2D films vs. 1D wires allows for a greater dynamic range. Furthermore, our fabrication method uses thermal evaporation of metal and application of selfassembled monolayers of siloxane which are similar to techniques used in producing integrated circuit and hence amenable to mass production. This Argonne developed technology has received numerous inquiries from industry, is receiving additional Phase I and II funding with our industrial partner who is negotiating an exclusive license of the patent rights and this is being submitted for an R&D100 award.
2.
The extrinsic properties of nanocrystals are mainly determined by size, shape, composition, and crystallinity. By controlling the electrode potential in dilute, low ionic strength plating baths as outlined in J Am Chem Soc, 126, 2316 (2004), one can control any one of these parameters to fine-tune the properties of nanocrystals in any size from under 200nm to over 10µm. Unlike most other methods for making shaped mesostructures, the results of our electrodeposition studies are untemplated, single or multiply twinned crystals. Such 3D crystals provide unique samples – unavailable by any other synthesis technique – for (i) exploring the nucleation of superconductivity in 3D nanostructures; (ii) altering the vortex shapes in quasi-fractal shaped meso-structures (iii) tailoring the band structure by size & shape, and (iv) changing the effective catalytic activity of nanocatalysts through shape control.
3.
Controlled-shape 3D mesoscopic superconductors where all three dimensions are comparable to the superconducting length scales ? (penetration depth) and ? (coherence length) heralds a new paradigm to explore vortex confinement effects. In these electrochemically grown crystals, the surface and shape of the meso-crystals become the dominant factors which determine the stability of the vortex structure. We present ballistic micro-Hall probe magnetization measurements on a single mesoscopic crystal of Pb, shaped like a triangular prism with faceted edges. Magnetization measurements demonstrate the stability of high vorticity L states with single flux quanta entry and exit into the sample at low temperatures. In contrast, a clear Meissner state is observed at high temperatures with very stable low vorticity states. Our results indicate that these novel 3D-architectured meso-superconducting crystals can be tuned to exhibit type I and type II behavior with temperature! A full 3D Ginzburg-Landau calculation predicts a novel phase consisting of Abrikosov vortices co-existing with a multi-quanta giant vortex state in these shaped crystals due to the strong effect of the confining geometrical shape on the vortex
New Endeavors
I am currently an Assistant Professor of Chemistry at University of Wisconsin - Stevens Point . I am very interested in trying to encourage some of our best and brightest students to find their niche in scientific research and to help satisfy our national need for new innovations. I do this through trying to engage students in class by using many personal experiences from Berkeley and Argonne National Laboratory to pique their interests. I am also involved in outreach to many elementary, secondary and high schools. My work at Argonne with the World's fastest commercially producible hydrogen sensors that won the R&D 100 Award is a great inspiration and serves to get a lot of students very excited about science. The research that my students and I focus on at UWSP is the electrodeposition of nanostructures and continuing development of hydrogen sensors. The collaboration with scientists at Argonne continues and with my first and most difficult year of university teaching completed. I hope to be able to start bringing samples and students to Argonne in collaborative projects on a regular basis.
Other information :
Holds a residence associate appointment in the MSD Division
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