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Full-Text Articles in Physics

Variation Of Magnetostriction With Temperature In Tb5si2.2ge1.8 Single Crystal, A. P. Ring, H. L. Ziegler, Thomas A. Lograsso, Deborah L. Schlagel, J. E. Snyder, David C. Jiles Apr 2006

Variation Of Magnetostriction With Temperature In Tb5si2.2ge1.8 Single Crystal, A. P. Ring, H. L. Ziegler, Thomas A. Lograsso, Deborah L. Schlagel, J. E. Snyder, David C. Jiles

Ames Laboratory Conference Papers, Posters, and Presentations

The Tb5(SixGe4−x) alloy system is similar to the better known Gd5(SixGe4−x), except it has a more complex magnetic and structural phase diagram. Gd5(SixGe1−x)4 has received much attention recently due to its giant magnetocaloric effect, colossal magnetostriction and giant magnetoresistance in the vicinity of a first order combined magnetic-structural phase transition. The magnetostriction changes that accompany the phase transitions of single crystal Tb5(Si2.2Ge1.8) have been investigated at temperatures between 20 and150 K by measurements of ...


Magnetostructural Transitions And Adiabatic Temperature Variation In Polycrystal And Single-Crystal Ni2mnga Alloys, C. P. Sasso, M. Pasquale, L. Giudici, S. Besseghini, E. Villa, L. H. Lewis, Thomas A. Lograsso, Deborah L. Schlagel Apr 2006

Magnetostructural Transitions And Adiabatic Temperature Variation In Polycrystal And Single-Crystal Ni2mnga Alloys, C. P. Sasso, M. Pasquale, L. Giudici, S. Besseghini, E. Villa, L. H. Lewis, Thomas A. Lograsso, Deborah L. Schlagel

Ames Laboratory Conference Papers, Posters, and Presentations

The magnetocaloric response of off-stoichiometric Ni2MnGa polycrystal and single-crystal samples with a Curie temperature coincident with the martensitic transition temperature was investigated. The direct measurement of temperature change (ΔTad) during an adiabatic transformation under a maximum field variation ΔH = 5.6×106 A/m (7 T) was performed. The polycrystalline sample shows a maximum ΔTad ≈ 1.5 K at a temperature close to the structural transition. The value of ΔTad and the 20 K span of the ΔTad peak encourage further studies of the effect of microstructure on ...


Spontaneous Generation Of Voltage In Single-Crystal Gd5si2ge2 During Magnetostructural Phase Transformations, Min Zou, H. Tang, Deborah L. Schlagel, Thomas A. Lograsso, Karl A. Gschneidner Jr., Vitalij K. Pecharsky Apr 2006

Spontaneous Generation Of Voltage In Single-Crystal Gd5si2ge2 During Magnetostructural Phase Transformations, Min Zou, H. Tang, Deborah L. Schlagel, Thomas A. Lograsso, Karl A. Gschneidner Jr., Vitalij K. Pecharsky

Ames Laboratory Conference Papers, Posters, and Presentations

The spontaneous generation of voltage (SGV) in single-crystal and polycrystallineGd5Si2Ge2 during the coupled magnetostructural transformation has been examined. Our experiments show reversible, measurable, and repeatable SGV responses of the materials to the temperature and magnetic field. The parameters of the response and the magnitude of the signal are anisotropic and rate dependent. The magnitude of the SGV signal and the critical temperatures and critical magnetic fields at which the SGV occurs vary with the rate of temperature and magnetic-field changes.


Lattice And Spin Dynamics In Bcc Fe, 10 At. % Be, P. Zhao, J. Cullen, M. Wuttig, H. J. Kang, J. W. Lynn, Thomas A. Lograsso, O. Moze Apr 2006

Lattice And Spin Dynamics In Bcc Fe, 10 At. % Be, P. Zhao, J. Cullen, M. Wuttig, H. J. Kang, J. W. Lynn, Thomas A. Lograsso, O. Moze

Ames Laboratory Conference Papers, Posters, and Presentations

Body centered cubic Fe1−xBex alloys are known to display an enhanced tetragonal magnetostriction compared to Fe. In order to characterize the enhanced magnetoelasticity observed in this alloy system, we present detailed inelastic neutron scattering measurements of the phonon dispersion relations of a single crystal of bcc Fe, 10 at. %Be along the high symmetry directions [100], [110], and [111] at room temperature. We observe in particular that the frequency of transverse phonons propagating along the [110] direction with a [10] polarization at the zone boundary is reduced by 10% with respect to bcc Fe (the corresponding ...