513 research outputs found
Effects of Cognitive Fatigue on High Intensity Circuit Exercise: Preliminary study
Please refer to the pdf version of the abstract located adjacent to the title
Dzyaloshinskii-Moriya interaction and spin re-orientation transition in the frustrated kagome lattice antiferromagnet
Magnetization, specific heat, and neutron scattering measurements were
performed to study a magnetic transition in jarosite, a spin-5/2 kagome lattice
antiferromagnet. When a magnetic field is applied perpendicular to the kagome
plane, magnetizations in the ordered state show a sudden increase at a critical
field H_c, indicative of the transition from antiferromagnetic to ferromagnetic
states. This sudden increase arises as the spins on alternate kagome planes
rotate 180 degrees to ferromagnetically align the canted moments along the
field direction. The canted moment on a single kagome plane is a result of the
Dzyaloshinskii-Moriya interaction. For H < H_c, the weak ferromagnetic
interlayer coupling forces the spins to align in such an arrangement that the
canted components on any two adjacent layers are equal and opposite, yielding a
zero net magnetic moment. For H > H_c, the Zeeman energy overcomes the
interlayer coupling causing the spins on the alternate layers to rotate,
aligning the canted moments along the field direction. Neutron scattering
measurements provide the first direct evidence of this 180-degree spin rotation
at the transition.Comment: 13 pages, 15 figure
Magnetic structure of Yb2Pt2Pb: Ising moments on the Shastry-Sutherland lattice.
Neutron diffraction measurements were carried out on single crystals and powders of Yb2Pt2Pb, where Yb moments form two interpenetrating planar sublattices of orthogonal dimers, a geometry known as Shastry-Sutherland lattice, and are stacked along the c axis in a ladder geometry. Yb2Pt2Pb orders antiferromagnetically at TN=2.07K, and the magnetic structure determined from these measurements features the interleaving of two orthogonal sublattices into a 5×5×1 magnetic supercell that is based on stripes with moments perpendicular to the dimer bonds, which are along (110) and (−110). Magnetic fields applied along (110) or (−110) suppress the antiferromagnetic peaks from an individual sublattice, but leave the orthogonal sublattice unaffected, evidence for the Ising character of the Yb moments in Yb2Pt2Pb that is supported by point charge calculations. Specific heat, magnetic susceptibility, and electrical resistivity measurements concur with neutron elastic scattering results that the longitudinal critical fluctuations are gapped with ΔE≃0.07meV
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