GOALI: Nanoscale Characterization and Manipulation of Magnetoelastic Coupling and Magnetic Domains by Novel Quantitative Scanning Probe Microscopy

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TECHNICAL SUMMARY: The objective of this project is to understand the dramatically enhanced magnetostriction in Galfenol, or Fe-Ga alloy, which exhibits magnetostrictive strain one order of magnitude higher than that of alpha-Fe, even though Ga is nonmagnetic. Novel piezomagnetic force microscopy (PmFM) will be developed through the collaboration between the University of Washington and Asylum Research, which will enable quantitative characterization and manipulation of magnetoelastic coupling and magnetic domains with high sensitivity, high spatial resolution, and minimized cross-talk with topography. Magnetostrictive response and magnetic domains of Galfenol will be mapped and manipulated at the nanoscale using the proposed PmFM technique, and the obtained real space magnetoelastic response will be correlated with the underlying microstructure of Galfenol determined from detailed structural analysis. Modeling and simulation of the configuration and evolution of magnetic domains and transforming microstructures of Galfenol will also be carried out to link the nanoscale magnetostrictive response and macroscopic magnetostriction measurement. Through the tightly coupled experimental and theoretical investigations, the project will help to clarify the microscopic mechanism responsible for the enhanced magnetostriction in Galfenol.NON-TECHNICAL SUMMARY: Magnetostriction refers to magnetic field induced strain in ferromagnetic materials, and Galfenol is an emerging class of structural magnetostrictive material with excellent mechanical properties. It is promising for a wide range of applications in mechanically tough environments, such as underwater sonar transduction and damping or energy harvesting of mechanical vibrations, in which conventional giant magnetostrictive materials are not suitable because of their poor mechanical strength. The project will help to understand the microscopic mechanism responsible for the enhanced magnetostriction in Galfenol, and potentially guide the development of new structural magnetostrictive materials with even better properties. A novel scanning probe microscopy technique will also be developed, which can be applied to study a wide range of magnetic materials with enhanced sensitivity and resolution over the state of art magnetic force microscopy. Graduate and undergraduate students will be trained through integrated research and education that involve extensive collaborations with industry, and outreach activities will also be developed for high school students and teachers.