Four-Year College Faculty-Student Team Fellowships Program
Example: Polarization Image
Prof. Horacio Vasquez and student Stella Stephens from the University of Texas - Pan American
Worked with Stephen Ducharme, Physics.
“This summer, we have developed a computer program and implemented an automatic nano-positioning system to perform scanning on the surface of pyroelectric material samples to image their polarization. The sample we are using is a ferroelectric film consisting of 40 monolayers of vinylidene fluoride and trifluoroethylene, P(VDF-TRFE), fabricated using Langmuir-Blodgett (LB) deposition techniques, and it is between two aluminum electrodes. An electronically modulated laser beam was focused on the top electrode of the sample to generate a pyroelectric current that is proportional to the spontaneous polarization of the area on which the laser beam is acting. This automatic system allows us to set the desired scanning path and the number of points to be scanned in each of the “x” and “y” axis up to 20 μm, in step sizes as low as 5 nm. New research to determine pyroelectric material polarization at the nano-positioning level can be conveniently performed with this new system.”
Worked with Jeff Shield, Mechanical Engineering.
“We’re working with nanoscale permanent magnetic materials. Meghan studies NdFeB and Marlann studies FePt. The goal of the research is to make clusters of these materials on a small enough size scale that their magnetic properties are enhanced. The method for making these materials is called gas-phase aggregation, and is done in a dc plasma sputtering machine. This method is used because of our ability to control the size distribution of the clusters. Meghan has had fun learning about the thought process behind research and Marlann has had fun interacting with other scientists and students doing research.
Thanks, MRSEC, for the opportunity!"
Worked with Sy-Hwang Liou, Physics.
Michael Parker and Craig Meeks worked primarily with an Alternating Gradient Force Magnetometer (AGFM) which they used to collect hysteresis data that was used to produce First Order Reversal Curve (FORC) diagrams. They interpreted these FORC diagrams on the basis of models that describe the interaction between ferromagnetic clusters and domains. Such information of materials is not readily observed, by utilizing hysteresis loops alone. They applied their studies to memory devices and on the phenomenological effect of switching due to the varying thicknesses of a Ni/O spacer between Co/Pt multilayers.
Worked with Diandra Leslie-Pelecky, Physics.
“Our project consisted of exploring sputter deposition conditions to produce stable high moment magnetic fluids that could be used for targeted drug delivery. The temperature gradient between the target and the oil deposition surface was found to be critical for particles to form in the vapor phase. Depositions that produced large enough particles were able to be separated from the oil for structural and magnetic analysis. On these samples transmission electron microscopy (TEM) provided details about the particle morphology (such as the size, shape, and amount of agglomeration), x-ray and electron diffraction provided information on the crystalline phases present in the sample and an alternating gradient force magnetometer (AGFM) provided magnetic information. This information will be used to develop magnetic fluids viable for targeted drug delivery.”
Worked with David Sellmyer, Physics.
“Our research focused on the preparation of magnetic multilayers for ultra high density data storage and their characterization by ferromagnetic resonance and x-ray diffraction. The goal of this research was a better understanding of the interactions between magnetic layers spaced by non-magnetic materials, with emphasize on the evolution of electronic spins in external magnetic fields. Ferromagnetic resonance is a unique experimental technique that senses directly the electronic spins and their interactions. Complementary structural data were obtained by x-ray diffraction investigations and included in the analysis of ferromagnetic resonance data.”
Worked with Diandra Leslie-Pelecky, Physics.
“Our research is based on a vapor deposition sputtering technique, in which iron nanoparticles are deposited into a bath of oil. These particles have to be a specific size and non oxidized, so we are trying to coat the particles in a chemical called a surfactant. The surfactant will prevent the particles from becoming too big and slow their oxidation rate. The ultimate goal for these particles is to be able to attach drugs to them so they can be located to a certain place in the body through a magnetic field, at which point they will start fighting the disease.”