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Full-Text Articles in Physics

Texture And Grain Morphology Dependencies Of Saturation Magnetostriction In Rolled Polycrystalline Fe83ga17, R. A. Kellogg, A. B. Flatau, A. E. Clark, M. Wun-Fogle, Thomas A. Lograsso May 2013

Texture And Grain Morphology Dependencies Of Saturation Magnetostriction In Rolled Polycrystalline Fe83ga17, R. A. Kellogg, A. B. Flatau, A. E. Clark, M. Wun-Fogle, Thomas A. Lograsso

Ames Laboratory Conference Papers, Posters, and Presentations

Textured polycrystalline Fe-Ga alloys exhibit magnetostrictive strains of 100 ppm or greater and may function as a mechanically robust actuator/sensing material. Current efforts seek to combine the 300+ ppm magnetostrictive strain performance of [100] oriented single crystals with the mechanical properties of polycrystalline forms. One approach to combining these properties is to control the crystallographic texture through deformation processing such as rolling. To determine the relationship between saturation magnetostriction, degree of texturing, and grain morphology we compare the results of three-dimensional finite element simulations with the analytical solution for a random polycrystal and the experimental responses of rolled polycrystalline ...


Magnetism Dependent Phonon Anomaly In Lafeaso Observed Via Inelastic X-Ray Scattering, Steven E. Hahn, Gregory S. Tucker, J.-Q. Yan, A. H. Said, B. M. Leu, R. William Mccallum, E. E. Alp, Thomas A. Lograsso, Robert J. Mcqueeney, Bruce N. Harmon Apr 2013

Magnetism Dependent Phonon Anomaly In Lafeaso Observed Via Inelastic X-Ray Scattering, Steven E. Hahn, Gregory S. Tucker, J.-Q. Yan, A. H. Said, B. M. Leu, R. William Mccallum, E. E. Alp, Thomas A. Lograsso, Robert J. Mcqueeney, Bruce N. Harmon

Ames Laboratory Conference Papers, Posters, and Presentations

The phonon dispersion was measured at room temperature (above the Néel temperature TN) along (0,0,L) in the tetragonal phase of LaFeAsO using inelastic x-ray scattering. Magnetostructural effects are well documented in the AFe2As2-based (A = Ca, Sr, Ba, Eu) systems. Only recently have single crystals of LaFeAsO become available. The experimentally observed splitting between two A1g phonon modes at 22 and 26 meV is only reproduced in spin-polarized calculations. Magnetostructural effects similar to those observed in the AFe2As2 materials are confirmed to be present in LaFeAsO. This is discussed ...


Photoinduced Femtosecond Formation Of Ferromagnetism In A Strongly Correlated Antiferromagentic Manganite, T. Li, A. Patz, J. Yan, Thomas A. Lograsso, I. E. Perakis, J. Wang Jan 2013

Photoinduced Femtosecond Formation Of Ferromagnetism In A Strongly Correlated Antiferromagentic Manganite, T. Li, A. Patz, J. Yan, Thomas A. Lograsso, I. E. Perakis, J. Wang

Ames Laboratory Conference Papers, Posters, and Presentations

We report a pump threshold behavior in fs photoinduced magnetization in a strongly correlated manganite, which indicates the establishment of thermally-inaccessible ferromagnetic ground state and build-up of new magnetic order parameters at fs time scales.