127 research outputs found
Lack of static lattice distortion in
We investigated the possibility of temperature dependent lattice distortions
in the pyrochlore compound TbTiO by measuring the internal
magnetic field distribution, using muon spin resonance, and comparing it to the
susceptibility. The measurements are done at temperatures as low as 70 mK and
external fields up to 6 kG. We find that the evolution of the width of the
field distribution can be explained by spin susceptibility only, thus ruling
out a temperature dependent hyperfine coupling. We conclude that lattice
deformations are absent in TbTiO.Comment: 8 pages, 5 figures, accepted for publication in J. Phys. Condens.
Matter. (Proceedings of Highly Frustrated Magnetism 2006); Corrections of
various typo
The symmetry of the spin Hamiltonian in herbertsmithite, a spin-1/2 kagom\'{e} lattice
We present magnetization measurements on oriented powder of
ZnCu(OH)Cl along and perpendicular to the orienting field. We
find a dramatic difference in the magnetization between the two directions. It
is biggest at low measurement fields or high temperatures. We show that the
difference at high temperatures must emerge from Ising-like exchange
anisotropy. This allows us to explain muon spin rotation data at in
terms of an exotic ferromagnetic ground state.Comment: 5 pages, 5 figure
Nutation versus angular dependent NQR spectroscopy and the impact of underdoping on charge inhomogeneities in YBaCuO
We describe two different nuclear quadrupole resonance (NQR) based
techniques, designed to measure the local asymmetry of the internal electric
field gradient, and the tilt angle of the main NQR principal axis z from the
crystallographic axis c. These techniques use the dependence of the NQR signal
on the duration of the radio frequency (rf) pulse and on the direction of the
rf field H1 with respect to the crystal axis. The techniques are applied to
oriented powder of YBaCuO fully enriched with 63Cu.
Measurements were performed at different frequencies, corresponding to
different in-plane copper sites with respect to the dopant. Combining the
results from both techniques, we conclude that oxygen deficiency in the chain
layer lead to a rotation of the NQR main principal axis at the nearby Cu on the
CuO2 planes by 20+-degrees. This occurs with no change to the asymmetry. The
axis rotation associated with oxygen deficiency means that there must be
electric field inhomogeneities in the CuO2 planes only in the vicinity of the
missing oxygen.Comment: 9 pages, 10 figure
What\u27s in a Stream? Understanding Video Gamers\u27 Perceptions regarding Streaming and its Legitimacy
Video game streaming – live interactive broadcasts of gameplay on online platforms such as YouTube, has emerged as an important phenomenon in the world of video games, with leading streamers attracting the viewership of millions. The public’s perception of streaming, and its legitimacy, is still very much undecided. We seek to understand gamers’ and streamers’ normative perceptions of streaming. Employing an extreme case study methodology, we analyze the Reddit discussion threads and streamers’ video-blogs following the decision of a game producer, Altus, to restrict streaming of its Persona 5 game. We reveal ambiguities amongst community regarding the nature of streaming, with perceptions ranging between streaming as a broadcast of game, a creative performance, or a community activity. Further, we discover the factors that influence gamers’ perceptions regarding streaming legitimacy. We discuss implications for HCI and IS research and practice
A quest for frustration driven distortion in Y2Mo2O7
We investigated the nature of the freezing in the geometrically frustrated
Heisenberg spin-glass Y2Mo2O7 by measuring the temperature dependence of the
static internal magnetic field distribution above the spin-glass temperature,
Tg, using the muSR technique. The evolution of the field distribution cannot be
explained by changes in the spin susceptibility alone and suggests a lattice
deformation. This possibility is addressed by numerical simulations of the
Heisenberg Hamiltonian with magneto-elastic coupling at T>0.Comment: 5 pages 4 figures. Accepted for publication in PR
Charge-Inhomogeneity doping relations in YBCO detected by Angle Dependent Nuclear Quadrupole Resonance
The origin of charge inhomogeneity in YBa_{2}Cu_{3}O_{y} is investigated
using a new experimental method designed to determine the nuclear quadrupole
resonance (NQR) asymmetry parameter eta for very wide NQR lines at different
positions on the line. The method is based on the measurement of the echo
intensity as a function of the angle between the radio frequency field H1 and
the principal axis of the electric field gradient. Static charge inhomogeneity
deduced from eta>0 are found in this compound, but only in conjunction with
oxygen deficiency. This limits considerably the possible forms of charge
inhomogeneity in bulk YBa_{2}Cu_{3}O_{y}.Comment: To be published in Phys. Rev. B; Revised version with a correction to
figure
The Herbertsmithite Hamiltonian: SR measurements on single crystals
We present transverse field muon spin rotation/relaxation measurements on
single crystals of the spin-1/2 kagome antiferromagnet Herbertsmithite. We find
that the spins are more easily polarized when the field is perpendicular to the
kagome plane. We demonstrate that the difference in magnetization between the
different directions cannot be accounted for by Dzyaloshinksii-Moriya type
interactions alone, and that anisotropic axial interaction is present.Comment: 8 pages, 3 figures, accepted to JPCM special issue on geometrically
frustrated magnetis
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