Structure–Composition-Magnetostriction Correlations in Strong

and Ductile Fe-Based Alloys with Large Low-Field Magnetostriction

Sivaraman Guruswamy, University of Utah, DMR 0854166

Research Focus• Magnetostriction refers to the change in the length

of a material with applied magnetic field

• Magnetostrictive materials are used in numerous sensors and actuator applications: sonar, nano-positioning, load sensors, ABS, active damping, …

• Research examines how local atomic environment, crystalline structure and crystal defects influence the magnetostriction in a-Fe based alloys.

Nanoscale coherent second phase regions in Fe-27.5Ga annealed alloy that drastically reduce magnetostriction

Technical and Scientific ImpactThis is a significant contribution to a fundamental understanding of magnetostriction and towards alloy design for sensor and actuators, (as well as low-/zero-expansion alloys and magnetic data storage devices where we need to control this behavior).

Significant Findings Controlling inhomogeneous elastic strains introduced by modifying local atomic spacing by solutes and defects, is key to controlling the magnetostriction.

EXAFS* data (R) as a function of R and the fit obtained at the Ga K edge from Fe-27.5 at.% Ga DO3 ordered single crystal using Advanced Photon Source at ANL. The preliminary model fits show shortening of the Ga-Ga near neighbor distances relative to Ga-Fe distances indicating the presence of local distortions arising from Ga-Ga dimers.

* EXAFS-Extended X-ray Absorption Fine spectrum

Education, Training and Outreach• Undergraduate Gavin Garside (first one in his

family to pursue college education) and a female student Shamita Shitole have joined as graduate students on this project

• Students are being trained in alloy synthesis, crystal growth, SEM, TEM, XRD, magnetic measurements, and EXAFS data analysis

• Gavin Garside attended the 2009 Neutron and X-ray Scattering School at ORNL/ ANL

• Showcased the lab and research during Science day 2008, Dept. Open House (2009) and ASM Open House (2009) to high school students/ public

Structure–Composition-Magnetostriction Correlations in Strong

and Ductile Fe-Based Alloys with Large Low-Field Magnetostriction

Sivaraman Guruswamy, University of Utah, DMR 0854166

Recognitions/ Economic Impact• A new company to commercialize the technology is

being spun off in 2009• Honorable mention, Utah Innovation Awards, 2009• PI organized the Global Innovations Plenary

Symposia on “Energy Harvesting” and “Photovoltaics and Thermoelectrics” at TMS 2009

Graduate student Gavin Garside making a poster presentation at the Utah ASM student poster contest

Graduate student Shamita trained in the use of XRD system

PI showcasing the Lab and research to visitors during ASM open house

Graduate students Gavin and Shamita preparing the alloy by arc melting prior to single crystal growth