Magnetoelastic Interactions in Giant Magnetostriction Multilayers for Adaptive Micro-systems Transducers

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PIs: R. C. Wetherhold and Harsh Deep Chopra, State University of New York at BuffaloProposal Number: 0099830Proposal Title: Magneto-Elastic Interactions in Giant Magnetostriction Multilayersfor Adaptive Micro-Systems TransducersProject Abstract: Research is focused on high strain susceptibility and low switching field "giant" magnetostriction of Tb-Fe or Sm-Fe films, which are sandwiched between high magnetization soft magnets, such as Fe-Co. Due to inter-layer interactions between stress and magnetization in these multilayers, understanding and controlling favorably the magneto-elastic coupling is a key objective of these studies. An overall energy function is being developed for the combination of all magnetic, mechanical, and coupling energies, in order to understand the magneto-elastic coupling. Multilayers are being sputter deposited as a function of layer thickness and number of bilayers, with post-deposition stress annealing to optimize their magneto-elastic behavior. Films are being characterized for their magnetic structure and microstructure using analytical electron microscopy, x-ray diffraction, and scanning probe microscopy. Optimized films are being tested as adaptive components of micro-electro-mechanical systems (MEMS) and Bio-MEMS. In addition to the richness of new phenomena that are being observed due to magneto-elastic interactions, these studies impact significantly the rapidly evolving fields of MEMS and bio-MEMS. Examples include highly efficient micro-switches, laser beam deflectors, fluid jet deflectors, valves, ultrasonic motors, micro-grippers and micro-pumps, with high dynamic response. Educational impact includes active training and participation of graduate and undergraduate students, as well as high school students from Buffalo area inner city high schools.