143 research outputs found
Confirmation of a one-dimensional spin-1/2 Heisenberg system with ferromagnetic first-nearest-neighbor and antiferromagnetic second-nearest-neighbor interactions in RbCuMoO
We have investigated magnetic properties of RbCuMoO
powder. Temperature dependence of magnetic susceptibility and magnetic-field
dependence of magnetization have shown that this cuprate is a model compound of
a one-dimensional spin-1/2 Heisenberg system with ferromagnetic
first-nearest-neighbor (1NN) and antiferromagnetic second-nearest-neighbor
(2NN) competing interactions (competing system). Values of the 1NN and 2NN
interactions are estimated as K and K (). This value of suggests that the ground state is a
spin-singlet incommensurate state. In spite of relatively large and
, no magnetic phase transition appears down to 2 K, while an
antiferromagnetic transition occurs in other model compounds of the competing
system with ferromagnetic 1NN interaction. For that reason,
RbCuMoO is an ideal model compound to study properties of
the incommensurate ground state that are unconfirmed experimentally.Comment: 6 pages, 4 figure
Spiral magnetic structure in spin-5/2 frustrated trimerized chains in SrMn3P4O14
We study a spin-5/2 antiferromagnetic trimerized chain substance SrMn3P4O14
using neutron powder diffraction experiments. The coplanar spiral magnetic
structure appears below T_N1 = 2.2(1) K. Values of several magnetic structure
parameters change rapidly at T_N2 = 1.75(5) K, indicating another phase
transition, although the magnetic structures above and below T_N2 are the
qualitatively same. The spiral magnetic structure can be explained by
frustration between nearest-neighbor and next-nearest-neighbor exchange
interactions in the trimerized chains.Comment: submitted to Phys. Rev.
Three-dimensional finite element analysis of Aramany Class IV obturator prosthesis with different clasp designs.
The purpose of this study was to evaluate the stress distribution on the alveolar bone surrounding abutment teeth and the displacement of the Aramany Class IV obturator prosthesis with two different clasp designs. Three-dimensional finite element models of an Aramany Class IV maxillary defect were constructed. Two different clasp designs on an obturator prosthesis (double Akers clasps and multiple Roach clasps) and two different load conditions (vertical and horizontal) were compared. Finite element analysis was used to calculate the equivalent stress. The difference in the clasp design of the Aramany Class IV obturator prosthesis affected the stress distribution of the alveolar bone surrounding the abutment teeth and the displacement of the obturator prosthesis. Multiple Roach clasps reduced the stress distribution on the alveolar bone surrounding the abutment teeth and the displacement of the Aramany Class IV obturator prosthesis compared to double Akers clasps.福岡歯科大学2013年
Sheet Dependence on Superconducting Gap in Oxygen-Deficient Iron-based Oxypnictide Superconductors NdFeAs0.85
Photoemission spectroscopy with low-energy tunable photons on
oxygen-deficient iron-based oxypnictide superconductors NdFeAsO0.85 (Tc=52K)
reveals a distinct photon-energy dependence of the electronic structure near
the Fermi level (EF). A clear shift of the leading-edge can be observed in the
superconducting states with 9.5 eV photons, while a clear Fermi cutoff with
little leading-edge shift can be observed with 6.0 eV photons. The results are
indicative of the superconducting gap opening not on the hole-like ones around
Gamma (0,0) point but on the electron-like sheets around M(pi,pi) point.Comment: 8 pages, 3 figure
Magnetotelluric and temperature monitoring after the 2011 sub-Plinian eruptions of Shinmoe-dake volcano
Three sub-Plinian eruptions took place on 26–27 January 2011 at Shinmoe-dake volcano in the Kirishima volcanic group, Japan. During this event, GPS and tiltmeters detected syn-eruptive ground subsidence approximately 7 km to the WNW of the volcano. Starting in March 2011, we conducted broad-band magnetotelluric (MT) measurements at a site located 5 km NNW of the volcano, beneath which the Shinmoe-dake magma plumbing system may exist. In addition, temperature monitoring of fumaroles and hot-springs near the MT site was initiated in July 2011. Our MT data record changes in apparent resistivity of approximately ±5%, along with a ±1◦ phase change in the off-diagonal component of the impedance tensor (Zxy and Zyx ). Using 1-D inversion, we infer that these slight changes in resistivity took place at relatively shallow depths of only a few hundred meters, at the transition between a near-surface resistive layer and an underlying conductive layer. Resistivity changes observed since March 2012 are correlated with the observed temperature increases around the MT monitoring site. These observations suggest the existence beneath the MT site of pathways which enable volatile escape
High-Energy Anomaly in the Band Dispersion of the Ruthenate Superconductor
We reveal a “high-energy anomaly" (HEA) in the band dispersion of the unconventional ruthenate superconductor Sr2RuO4, by means of high-resolution angle-resolved photoemission spectroscopy (ARPES) with tunable energy and polarization of incident photons. This observation provides another class of correlated materials exhibiting this anomaly beyond high-Tc cuprates. We demonstrate that two distinct types of band renormalization associated with and without the HEA occur as a natural consequence of the energetics in the bandwidth and the energy scale of the HEA. Our results are well reproduced by a simple analytical form of the self-energy based on the Fermi-liquid theory, indicating that the HEA exists at a characteristic energy scale of the multielectron excitations. We propose that the HEA universally emerges if the systems have such a characteristic energy scale inside of the bandwidth
Negative magnetization of Li2Ni2Mo3O12 having a spin system composed of distorted honeycomb lattices and linear chains
We study themagnetism of a spin-1 substance Li2Ni2Mo3O12. The spin system
consists of distorted honeycomb lattices and linear chains of Ni2+ spins. Li+
ions enter about 25% and 50% of the honeycomb and chain Ni sites, respectively,
creating disorder in both spin subsystems. A magnetic phase transition occurs
at Tc = 8.0 K in the zero magnetic field. In low magnetic fields, the
magnetization increases rapidly below Tc, decreases below 7 K, and finally
becomes negative at low temperatures. We determine the magnetic structure using
neutron powder diffraction results. The honeycomb lattices and linear chains
show antiferromagnetic and ferromagnetic long-range order, respectively. We
investigate static and dynamic magnetic properties using the local probe
technique of muon spin relaxation. We discuss the origin of the negative
magnetization
Two-photon excitable boron complex based on tridentate imidazo[1,5-a]pyridine ligand for heavy-atom-free mitochondria-targeted photodynamic therapy
We have synthesized a cyan fluorescent boron complex based on a tridentate imidazo[1,5-a]pyridine ligand. The boron complex was found to have potential applications as not only a chiroptical material but also a heavy-atom-free mitochondria-targeted photosensitizer for cancer treatment
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