Bulletin of the American Physical Society
2007 APS Four Corners Section/SPS Zone 16 Joint Fall Meeting
Volume 52, Number 14
Friday–Saturday, October 19–20, 2007; Flagstaff, Arizona
Session B1: Condensed Matter: Etching, Shapes and Surfaces |
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Chair: Colin Inglefield, Weber State University Room: Chemistry (Bldg. 20) Room 224 |
Friday, October 19, 2007 2:10PM - 2:22PM |
B1.00001: Discerning the Piezoelectric Quality of CdS Crystals and ZnO Films From Their Etch Properties Fred Hickernell, Thomas Hickernell Several tests have been used over the years to determine the quality of piezoelectric crystals and films. A test which has been found especially useful is chemical etching. Chemical etching, while destructive to a portion of the crystal or film, reveals considerable information which can be related to its piezoelectric quality. The characteristics of the etching of CdS and ZnO crystals or films is highly anisotropic depending upon whether the acid attacks the c-axis metal face or sulfide-oxide face, or lateral to the c-axis. The etch pit density per unit area is a useful parameter for both crystals and films and can be used for comparison purposes with piezoelectric related properties. For example by controlling the percentage of the acid etchant in water, direct comparisons can be made of film properties under different deposition conditions. Etch times for ZnO films extend as low as 200 Angstroms per second for high piezoelectric coupling factor films with dense uniform fiber grains and as high as 1000 Angstroms per second for nonuniform grain structures. This paper will present the results of etching studies on (1) crystalline CdS and (2) thin-film ZnO under sputter deposition. [Preview Abstract] |
Friday, October 19, 2007 2:22PM - 2:34PM |
B1.00002: Correction Model for Reflection off Rough Conductive Surfaces W. Todd Doughty, R. Steven Turley, Elise Martin, Jed Johnson We modeled the reflectance from rough surfaces of conductors for both TM and TE polarization. We used a Nystrom technique to solve the Electric Field Integral Equation in the TM case and the Magnetic Field Integral Equation in the TE case. We studied a large number of sample surfaces with varied roughness heights and frequencies from various incident angles and compared these results to the expected results from Debye-Waller. We determined that the Roughness correction is a function of $qh$, as is proposed by Debye Waller, where q is $2\pi\sin\theta/\lambda$ and $h$ is the rms surface roughness height. In addition to the quadratic term predicted, our simulations showed significant linear and cubic terms. These terms are especially significant for high spatial frequency roughness where the spatial frequency is on the order of a wavelength. [Preview Abstract] |
Friday, October 19, 2007 2:34PM - 2:46PM |
B1.00003: Remanent states of Cobalt nanostructures Kevin Winn Properties of ferromagnetic nanostructures are vital for the production of high density magnetic data storage. To increase density and reliability of magnetic data storage, understanding of the magnetization of these structures must be better understood. Cobalt nanostructures have been studied recently, finding that shape of the structure strongly determines the magnetization of the remnant state. Reliable data storage has created a need for a reliable and stable remnant states. To create structures of reliable remnant states more unique shapes have been investigated. Micro magnetic simulations of 30nm thick Cobalt structures were conducted and matched with data from off-axis electron holography. The Cobalt structures are 600 x 400 nm ellipse with slots and rings cut out, deforming the ellipse. The simulations provide values of total energy, exchange energy and energy density. Values of energies, paired with magnetic configurations (domain walls, vortexes and flux closer) allow details of the effect shape have on remnant states. These play a vital role in both reliability and reproducibility of the nanomagnet. Investigation of the effects caused by rings and slots in Cobalt ellipses, by use of magnetic simulations, creates a visual understanding, aiding in the formation of new and better magnetic structures. [Preview Abstract] |
Friday, October 19, 2007 2:46PM - 2:58PM |
B1.00004: Photochemical Reactivity of Ba1-xSrxTiO3 Solid Solutions Andrew Gamalski, Nina V. Burbure, Gregory S. Rohrer The photochemical reactivities of SrxBa1-xTiO3 solids solutions were investigated as a function of composition. Samples with x = 0 to 1 were used to reduce Ag+ in aqueous solution to Ag0 on the sample surface and the relative heights and densities of the silver deposits, as measured by atomic force microscopy, were used to quantify the relative reactivities. A local maximum in the reactivity is observed at x = 0.26, which is near the cubic-tetragonal phase boundary. Based on these observations, it is concluded that the increase in the dielectric constant at this composition increases the width of the depletion layer and this promotes electron transfer to the surface and increases the reactivity. [Preview Abstract] |
Friday, October 19, 2007 2:58PM - 3:10PM |
B1.00005: Coupling flexible solar cell with parabolic trough solar-concentrator-prototype design and performance Alexander Panin, Jonathon Bergquist Solar cells are still too expensive ({\$}5-{\$}20/watt) to compete with traditional fossil fuel power generating methods ($\sim ${\$}1/watt). Parabolic trough solar concentrator has the advantage of modest concentration ratio (10-100) which is well suited for coupling with solar cell. Thus using small area solar cell placed in the focal line of parabolic trough may be economically viable alternative to flat solar panels. We experiment with flexible solar cell (backed by water cooling pipe) placed in the focus of parabolic trough reflector. Another advantage of parabolic trough concentrator is very relaxed tracking requirement. For example, east-west oriented concentrator (aligned with the ecliptic plane) does not even need any tracking during core 4-6 hours around noon (when maximum illumination is available). The design and the performance of the prototype, as well as possible economical benefits of full scale projects are discussed in the presentation. [Preview Abstract] |
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