199 research outputs found
Neutron diffraction and Mössbauer study of the magnetic structure of YFe6Sn6
We have used time-of-flight (TOF) neutron powder diffraction, and both
57
Fe and
119
Sn
Mössbauer spectroscopy over the temperature range 2–600 K to determine the magnetic
ordering mode of the Fe sublattice in YFe6Sn6. The crystal structure is orthorhombic
(space group Immm). The Fe sublattice orders antiferromagnetically with a Néel
temperature of 558(5) K. The TOF neutron diffraction patterns obtained at 4 and 293 K
show that the antiferromagnetic ordering of the Fe sublattice is along [100] with a
propagation vector q=[010]. The magnetic space group is IPm′m′m′. This magnetic
structure is confirmed by our
119 Sn Mössbauer spectra
Dietary Anthocyanins: Impact on Colorectal Cancer and Mechanisms of Action
5-nonemixedTramer F.; Moze S.; Ademosun A.O.; Passamonti S.; Cvorovic J.Tramer, Federica; Moze, S.; Ademosun, A. O.; Passamonti, Sabina; Cvorovic, Jovan
Spin-wave dispersion in magnetostrictive Fe-Ga alloys: Inelastic neutron scattering measurements
Fe-Ga alloys of appropriate Ga concentration and heat treatment show a very large enhancement in the tetragonal magnetostriction over that of pure α-Fe [λ100(Fe-Ga)∼15λ100(Fe)]. In order to gain further understanding of the extraordinary magnetoelastic characteristics of this system, the spin dynamics of two of these alloys, Fe1−xGax (x=0.160 and 0.225), were studied using inelastic neutron scattering techniques. The correlation of the spin-wave dispersion curve with the lattice constant and atomic radii of solute is examined for this and other Fe alloys
Lattice and spin dynamics in bcc Fe, 10 at. % Be
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 elastic shear constant c′ = ½(c11−c12) associated with this mode is approximately 70% that of pure Fe). The dispersion of spin waves has also been determined for energy transfers up to 40 meV and is found to follow the isotropic dispersion relation E(q) = Dq2, with D ∼ 200 meV/Å2 [for Fe, E(q) = Dq2, with D = 280 meV/Å2]
Kondo Effects and Multipolar Order in the cubic PrTr2Al20 (Tr=Ti, V)
Our single crystal study reveals that PrTr2Al20 (Tr = Ti and V) provides the
first examples of a cubic {\Gamma}3 nonmagnetic ground doublet system that
shows the Kondo effect including a -ln T dependent resistivity. The {\Gamma}3
quadrupolar moments in PrV2Al20 induce anomalous metallic behavior through
hybridization with conduction electrons, such as T^{1/2} dependent resistivity
and susceptibility below ~ 20 K down to its ordering temperature T_O = 0.6 K.
In PrTi2Al20, however, quadrupoles are well-localized and exhibit an order at
T_O = 2.0 K. Stronger Kondo coupling in PrV2Al20 than in PrTi2Al20 suppresses
quadrupolar ordering, and instead promotes hybridization between the {\Gamma}3
doublet and conduction electrons, leading to most likely the quadrupolar Kondo
effect.Comment: 12 pages, 4 figure
- …