2,680 research outputs found
S wave superconductivity in newly discovered superconductor BaTiSbO revealed by Sb-NMR/Nuclear Quadrupole Resonance measurements
We report the Sb-NMR/nuclear quadrupole resonance (NQR)
measurements on the newly-discovered superconductor BaTiSbO with a
two-dimensional TiO square-net layer formed with Ti (3). NQR
measurements revealed that the in-plane four-fold symmetry is broken at the Sb
site below 40 K, without an internal field appearing at the Sb
site. These exclude a spin-density wave (SDW)/ charge density wave (CDW)
ordering with incommensurate correlations, but can be understood with the
commensurate CDW ordering at . The spin-lattice relaxation rate
, measured at the four-fold symmetry breaking site, decreases below
superconducting (SC) transition temperature , indicative of the
microscopic coexistence of superconductivity and the CDW/SDW phase below
. Furthermore, of Sb-NQR shows a coherence peak just
below and decreases exponentially at low temperatures. These
results are in sharp contrast with those in cuprate and iron-based
superconductors, and strongly suggest that its SC symmetry is classified to an
ordinary s-wave state.Comment: 5 pages, 6 figure
Method for producing heat-resistant semi-inorganic compounds
The method for producing a heat resistant, semi-inorganic compound is discussed. Five examples in which various alcohols, phenols, and aromatic carbonic acids are used to test heat resistance and solubility are provided
Organometalic carbosilane polymers containing vanadium and their preparation
The present invention concerns a new organometallic polymer material containing in part a vanadium-siloxane linkage (V-0-Si), which has excellent resistance to heat and oxidation and a high residue ratio after high temperature treatment in a non-oxidizing atmosphere, for example, nitrogen, argon, helium, ammonia, or hydrogen
Massive torsion modes, chiral gravity, and the Adler-Bell-Jackiw anomaly
Regularization of quantum field theories introduces a mass scale which breaks
axial rotational and scaling invariances. We demonstrate from first principles
that axial torsion and torsion trace modes have non-transverse vacuum
polarization tensors, and become massive as a result. The underlying reasons
are similar to those responsible for the Adler-Bell-Jackiw (ABJ) and scaling
anomalies. Since these are the only torsion components that can couple
minimally to spin 1/2 particles, the anomalous generation of masses for these
modes, naturally of the order of the regulator scale, may help to explain why
torsion and its associated effects, including CPT violation in chiral gravity,
have so far escaped detection. As a simpler manifestation of the reasons
underpinning the ABJ anomaly than triangle diagrams, the vacuum polarization
demonstration is also pedagogically useful. In addition it is shown that the
teleparallel limit of a Weyl fermion theory coupled only to the left-handed
spin connection leads to a counter term which is the Samuel-Jacobson-Smolin
action of chiral gravity in four dimensions.Comment: 7 pages, RevTeX fil
L^p boundedness of the wave operator for the one dimensional Schroedinger operator
Given a one dimensional perturbed Schroedinger operator H=-(d/dx)^2+V(x) we
consider the associated wave operators W_+, W_- defined as the strong L^2
limits as s-> \pm\infty of the operators e^{isH} e^{-isH_0} We prove that the
wave operators are bounded operators on L^p for all 1<p<\infty, provided
(1+|x|)^2 V(x) is integrable, or else (1+|x|)V(x) is integrable and 0 is not a
resonance. For p=\infty we obtain an estimate in terms of the Hilbert
transform. Some applications to dispersive estimates for equations with
variable rough coefficients are given.Comment: 26 page
Process for the production of metal nitride sintered bodies and resultant silicon nitride and aluminum nitride sintered bodies
A process for the manufacture of metal nitride sintered bodies, in particular, a process in which a mixture of metal nitrite powders is shaped and heated together with a binding agent is described. Of the metal nitrides Si3N4 and AIN were used especially frequently because of their excellent properties at high temperatures. The goal is to produce a process for metal nitride sintered bodies with high strength, high corrosion resistance, thermal shock resistance, thermal shock resistance, and avoidance of previously known faults
Coexistence of two- and three-dimensional Shubnikov-de Haas oscillations in Ar^+ -irradiated KTaO_3
We report the electron doping in the surface vicinity of KTaO_3 by inducing
oxygen-vacancies via Ar^+ -irradiation. The doped electrons have high mobility
(> 10^4 cm^2/Vs) at low temperatures, and exhibit Shubnikov-de Haas
oscillations with both two- and three-dimensional components. A disparity of
the extracted in-plane effective mass, compared to the bulk values, suggests
mixing of the orbital characters. Our observations demonstrate that Ar^+
-irradiation serves as a flexible tool to study low dimensional quantum
transport in 5d semiconducting oxides
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