1,099 research outputs found
The inferior caval vein draining into the left atrial cavity : a rare case
The inferior vena cava (IVC) draining into the left atrium (LA) is exceedingly rare in the setting of the usual atrial arrangement (situs solitus). This article describes a patient with this unique anomaly, and its repair.peer-reviewe
Studies on X-ray Thomson Scattering from Antiferroquadrupolar Order in TmTe
We study Thomson scattering from the antiferroquadrupole ordering phase in
TmTe. On the basis of the group theoretical treatment, we classify the
selection rules of the scattering intensity governed by the orientation of the
scattering vector G. Then, numerical verification is performed by invoking the
ground states which are deduced from a J=7/2 multiplet model. The obtained
intensity varies drastically depending on the magnitude and direction of G. We
also calculate the scattering intensities under the applied field for H//(001)
and (110). Their results behave differently when the orientation of G is
changed, which is ascribed to the difference of their primary order parameters;
O_{2}^{0} and O_{2}^{2} for H // (001) and (110), respectively. We make
critical comparisons between our results for TmTe and the experimental ones for
CeB_6. First, we assert that the intensities expected from TmTe at several
forbidden Bragg spots are sufficient enough to be experimentally detected.
Second, their intensities at (7/2,1/2,1/2) differ significantly and may be
attributed to the difference of the order parametersbetween the \Gamma_3-type
(O_{2}^{2} and O_{2}^{0}) and \Gamma_5-type (O_{yz}, O_{zx}, and O_{xy})
components, respectively.Comment: 18 pages, 3 figures, to be published in J. Phys. Soc. Jp
Spin nematic interaction in multiferroic compound BaCoGeO
We demonstrate the existence of the spin nematic interactions in an
easy-plane type antiferromagnet BaCoGeO by exploring the
magnetic anisotropy and spin dynamics. Combination of neutron scattering and
magnetic susceptibility measurements reveals that the origin of the in-plane
anisotropy is an antiferro-type interaction of the spin nematic operator. The
relation between the nematic operator and the electric polarization in the
ligand symmetry of this compound is presented. The introduction of the spin
nematic interaction is useful to understand the physics of spin and electric
dipole in multiferroic compounds.Comment: 5 pages, 4 figure
Determination of the Antiferroquadrupolar Order Parameters in UPd3
By combining accurate heat capacity and X-ray resonant scattering results we
have resolved the long standing question regarding the nature of the
quadrupolar ordered phases in UPd_3. The order parameter of the highest
temperature quadrupolar phase has been uniquely determined to be antiphase
Q_{zx} in contrast to the previous conjecture of Q_{x^2-y^2} . The azimuthal
dependence of the X-ray scattering intensity from the quadrupolar superlattice
reflections indicates that the lower temperature phases are described by a
superposition of order parameters. The heat capacity features associated with
each of the phase transitions characterize their order, which imposes
restrictions on the matrix elements of the quadrupolar operators.Comment: 4 pages, 5 figure
Antiferro-quadrupole Ordering of CeB Studied by Resonant X-ray Scattering
Under zero magnetic field, a quadrupolar order parameter at q_Q=(1/2,1/2,1/2)
in a typical antiferro-quadrupole (AFQ) ordering compound CeB6 has been
observed for the first time by means of a resonant X-ray scattering (RXS) te\
chnique. The RXS is observed at the 2p->5d dipole transition energy of the Ce
L3-edge. Using this RXS technique to observe the pure order parameter of the
AFQ state, the magnetic phase diagram of Phase II is first determined.Comment: 7 pages, 4 figure
Multipole tensor analysis of the resonant x-ray scattering by quadrupolar and magnetic order in DyB2C2
Resonant x-ray scattering (RXS) experiment has been performed for the (3 0
1.5) superlattice reflection in the antiferroquadrupolar and antiferromagnetic
phase of DyB2C2. Azimuthal-angle dependence of the resonance enhanced
intensities for both dipolar (E1) and quadrupolar (E2) resonant processes has
been measured precisely with polarization analysis. Every scattering channel
exhibits distinctive azimuthal dependence, differently from the symmetric
reflection at (0 0 0.5) which was studied previously. We have analyzed the
results using a theory developed by Lovesey et al., which directly connects
atomic tensors with the cross-section of RXS. The fitting results indicate that
the azimuthal dependences can be explained well by the atomic tensors up to
rank 2. Rank 3 and rank 4 tensors are reflected in the data very little. In
addition, The coupling scheme among the 4f quadrupolar moment, 5d ortitals, and
the lattice has been determined from the interference among the Thomson
scattering from the lattice distortion and the resonant scatterings of E1 and
E2 processes. It has also been established from the RXS of the (3 0 1.5)
reflection that the canting of the 4f quadrupolar moments exists up to T_Q. We
also discuss a possible wavefunction of the ground state from the point-charge
model calculation.Comment: 9 pages, 10 figure
Invariant Form of Hyperfine Interaction with Multipolar Moments - Observation of Octupolar Moments in NpO and CeB by NMR -
The invariant form of the hyperfine interaction between multipolar moments
and the nuclear spin is derived, and applied to discuss possibilities to
identify the antiferro-octupolar (AFO) moments by NMR experiments. The ordered
phase of NpO and the phase IV of CeLaB are studied in
detail. Recent O NMR for polycrystalline samples of NpO are
discussed theoretically from our formulation. The observed feature of the
splitting of O NMR spectrum into a sharp line and a broad line, their
intensity ratio, and the magnetic field dependence of the shift and of the
width can be consistently explained on the basis of the triple \bq AFO
ordering model proposed by Paix\~{a}o {\it et. al.} Thus, the present theory
shows that the O NMR spectrum gives a strong support to the model. The 4
O sites in the fcc NpO become inequivalent due to the secondary triple
\bq ordering of AF-quadrupoles: one cubic and three non-cubic sites. It turns
out that the hyperfine field due to the antiferro-dipole and AFO moments
induced by the magnetic field, and the quadrupolar field at non-cubic sites are
key ingredients to understand the observed spectrum. The controversial problem
of the nature of phase IV in CeLaB is also studied. It is
pointed out that there is a unique feature in the NMR spectra, if the
() AFO ordering is
realized in CeLaB. Namely, the hyperfine splitting of a B
atom pair on the sites crosses zero on the
plane when the magnetic field is rotated around the axis.Comment: 22 pages, 2 figure
Detection of Neutron Scattering from Phase IV of Ce0.7La0.3B6: A Confirmation of the Octupole Order
We have performed a single crystal neutron scattering experiment on
Ce0.7La0.3B6 to investigate the order parameter of phase IV microscopically.
Below the phase transition temperature 1.5 K of phase IV, weak but distinct
superlattice reflections at the scattering vector (h/2,h/2,l/2) (h, l = odd
number) have been observed by neutron scattering for the first time. The
intensity of the superlattice reflections is stronger for high scattering
vectors, which is quite different from the usual magnetic form factor of
magnetic dipoles. This result directly evidences that the order parameter of
phase IV has a complex magnetization density, consistent with the recent
experimental and theoretical prediction in which the order parameter is the
magnetic octupoles Tbeta with Gamma5 symmetry of point group Oh. Neutron
scattering experiments using short wavelength neutrons, as done in this study,
could become a general method to study the high-rank multipoles in f electron
systems.Comment: 4 pages, 4 figure
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