1,068 research outputs found
Strong Coupling between Antiferromagnetic and Superconducting Order Parameters in CeRhIn Studied by In-NQR Spectroscopy
We report on a novel pressure ()-induced evolution of magnetism and
superconductivity (SC) in a helical magnet CeRhIn with an incommensurate
wave vector through the In nuclear quadrupole
resonance (NQR) measurements under . Systematic measurements of the
In-NQR spectrum reveal that the commensurate antiferromagnetism (AFM)
with is realized above 1.7 GPa. An
important finding is that the size of SC gap and increase as the
magnitude of the AFM moment decreases in the region, where SC uniformly
coexists with the commensurate AFM. This result provides evidence of strong
coupling between the commensurate AFM order parameter (OP) and SC OP.Comment: 5 pages, 5 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
Anomalous quasiparticle transport in the superconducting state of CeCoIn5
We report on a study of thermal Hall conductivity k_xy in the superconducting
state of CeCoIn_5. The scaling relation and the density of states of the
delocalized quasiparticles, both obtained from k_xy, are consistent with d-wave
superconducting symmetry. The onset of superconductivity is accompanied by a
steep increase in the thermal Hall angle, pointing to a striking enhancement in
the quasiparticle mean free path. This enhancement is drastically suppressed in
a very weak magnetic field. These results highlight that CeCoIn_5 is unique
among superconductors. A small Fermi energy, a large superconducting gap, a
short coherence length, and a long mean free path all indicate that CeCoIn_5 is
clearly in the superclean regime (E_F/Delta<<l/xi), in which peculiar vortex
state is expected.Comment: 5 pages, 5 figure
Superconductivity without Local Inversion Symmetry; Multi-layer Systems
While multi-layer systems can possess global inversion centers, they can have
regions with locally broken inversion symmetry. This can modify the
superconducting properties of such a system. Here we analyze two dimensional
multi-layer systems yielding spatially modulated antisymmetric spin-orbit
coupling (ASOC) and discuss superconductivity with mixed parity order
parameters. In particular, the influence of ASOC on the spin susceptibility is
investigated at zero temperature. For weak inter-layer coupling we find an
enhanced spin susceptibility induced by ASOC, which hints the potential
importance of this aspect for superconducting phase in specially structured
superlattices.Comment: 4 pages, 2 figures, proceedings of the 26th International Conference
on Low Temperature Physics (LT26
Evolution of Paramagnetic Quasiparticle Excitations Emerged in the High-Field Superconducting Phase of CeCoIn5
We present In NMR measurements in a novel thermodynamic phase of CeCoIn5 in
high magnetic field, where exotic superconductivity coexists with the
incommensurate spin-density wave order. We show that the NMR spectra in this
phase provide direct evidence for the emergence of the spatially distributed
normal quasiparticle regions. The quantitative analysis for the field evolution
of the paramagnetic magnetization and newly-emerged low-energy quasiparticle
density of states is consistent with the nodal plane formation, which is
characterized by an order parameter in the Fulde-Ferrell-Larkin-Ovchinnikov
(FFLO) state. The NMR spectra also suggest that the spatially uniform
spin-density wave is induced in the FFLO phase.Comment: 4 pages, 4 figures, accepted for publication in Phys. Rev. Let
Novel phase diagram for antiferromagnetism and superconductivity in pressure-induced heavy-fermion superconductor CeRhIn probed by In-NQR
We present a novel phase diagram for the antiferromagnetism and
superconductivity in CeRhIn probed by In-NQR studies under pressure
(). The quasi-2D character of antiferromagnetic spin fluctuations in the
paramagnetic state at = 0 evolves into a 3D character because of the
suppression of antiferromagnetic order for 1.36 GPa (QCP:
antiferromagnetic quantum critical point). Nuclear-spin-lattice-relaxation rate
measurements revealed that the superconducting order occurs in the
range 1.36 -- 1.84 GPa, with maximum 0.9 K around
1.36 GPa.Comment: 5 pages, 5 figures, submitted to PR
^{115}In-NQR evidence for unconventional superconductivity in CeIn_3 under pressure
We report evidence for unconventional superconductivity in CeIn_3 at a
pressure P = 2.65 GPa above critical pressure (P_c ~ 2.5 GPa) revealed by the
measurements of nuclear-spin-lattice-relaxation time (T_1) and
ac-susceptibility (ac-chi). Both the measurements of T_1 and ac-chi have
pointed to a superconducting transition at T_c = 95 mK, which is much lower
than an onset temperature T_{onset} = 0.15 K at zero resistance. The
temperature dependence of 1/T_1 shows no coherence peak just below T_c,
indicative of an unconventional nature for the superconductivity induced in
CeIn_3.Comment: 4 pages, 4 figures, to be published in Phys.Rev.
Thermoelectric response near a quantum critical point: the case of CeCoIn5
We present a study of thermoelectric coefficients in CeCoIn_5 down to 0.1 K
and up to 16 T in order to probe the thermoelectric signatures of quantum
criticality. In the vicinity of the field-induced quantum critical point, the
Nernst coefficient nu exhibits a dramatic enhancement without saturation down
to lowest measured temperature. The dimensionless ratio of Seebeck coefficient
to electronic specific heat shows a minimum at a temperature close to threshold
of the quasiparticle formation. Close to T_c(H), in the vortex-liquid state,
the Nernst coefficient behaves anomalously in puzzling contrast with other
superconductors and standard vortex dynamics.Comment: 4 pages, 4 figures,final published versio
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