Synthesis and Characterization System for Magnetic Nanowire Arrays
Abstract
Instrumentation is requested to enable highly-repeatable synthesis of carefully engineered magnetic nanowire (MNW) arrays which are currently under investigation for two AFOSR projects, locally-heated nano ball grid arrays (nBGAs) and catalysts for arrays of vertically oriented carbon nanotubes. Both of these projects need arrays of MNWs that are electrochemically deposited inside insulating templates with columnar nanopores. The first critical step of the synthesis process is sputter deposition of a metallic contact layer onto the template, followed by electrodeposition before oxidation of either the front or back of this contact layer. The electrodeposition step occurs on the front of the contact layer which the electrolyte reaches at the bottom of the nanopores so the depositing metal is confined to form into columns, called nanowires. In our main project, these MNWs are then heated using an alternating magnetic field (AMF) rather than universal reflow ovens. The heating occurs by hysteresis losses. Both of these projects also need characterization of the MNWs, typically electron microscopy due to their sizes. The projects will advance significantly faster if the characterization and growth can undergo iterations for fine control of features, such as nanowire lengths. Three parts are requested- sputter deposition system, alternating magnetic field, and a tabletop scanning electron microscope. The sputter deposition system will be comprised of components available in Stadler’s lab and will be fully operable with the addition of software (including I-O cards), a turbomolecular pump, and installation costs. New levels of reproducibility will be possible with this deposition system in close proximity to Stadler’s electrochemical lab. The AMF also holds much promise for expanded results because it can be used to controllably alter the field strength and the switching frequency applied to the MNWs in dispersions or in the arrays. The field can be varied from 30 mT to 145 mT and the frequencies from 100 kHz to 450 kHz. MNWs can be designed to have rectangular hysteresis loops with coercivities from 10 kA-m to 145 kA-m. This AMF will therefore be tuned to optimize the best local heating with the lowest energy. Finally, a tabletop SEM is requested. As mentioned above, in several applications iterative imaging and growth will enable the MNWs to meet specs for optimal performance, such as catalyzing carbon nanotubes.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 29, 2024
- Source ID
- FA95502310314
Entities
People
- Bethanie Stadler
Organizations
- Air Force Office of Scientific Research
- Regents of the University of Minnesota
- United States Air Force