47th Annual Conference on Magnetism and Magnetic Materials
Extraordinary magnetostrictive behavior has been observed in Fe-Ga alloys with concentrations of Ga between 4% and 27%. λ100 exhibits two peaks as a function of Ga content. At room temperature, λ100 reaches a maximum of 265 ppm near 19% Ga and 235 ppm near 27% Ga. For compositions between 19% and 27%, λ100 drops sharply to a minimum near 24% Ga and exhibits an anomalous temperature dependence, decreasing by as much as a factor of 2 at low temperatures. This unusual magnetostrictive behavior is interpreted on the basis of a single maximum in the magnetoelastic coupling ∣b1∣ of Fe with increasing amounts of nonmagnetic Ga, combined with a strongly temperature dependent elastic shear modulus (c11−c12) which approaches zero near 27% Ga. λ111 is significantly smaller in magnitude than λ100 over this composition range, and has an abrupt change in sign from negative for low Ga concentrations to positive for a concentration of Ga near 21%.
American Institute of Physics
Clark, A. E.; Hathaway, K. B.; Wun-Fogle, M.; Restorff, J. B.; Lograsso, Thomas A.; Keppens, V. M.; Petculescu, G.; and Taylor, R. A., "Extraordinary magnetoelasticity and lattice softening in bcc Fe-Ga alloys" (2003). Ames Laboratory Conference Papers, Posters, and Presentations. 31.