4,125 research outputs found
Single crystal growth and physical properties of SrFe(AsP)
We report a crystal growth and physical properties of
SrFe(AsP). The single crystals for various s were
grown by a self flux method. For , reaches the maximum value of
30\,K and the electrical resistivity () shows -linear dependence.
As increases, decreases and () changes to -behavior,
indicating a standard Fermi liquid. These results suggest that a magnetic
quantum critical point exists around .Comment: 4 pages, 4 figures, accepted to Supplemental issue of the Journal of
Physical Society of Japan (JPSJ
Computation over galois fields using shiftregisters
This paper presents a technique for readily determining the shiftregister which multiplies by a given element of GF(2m)}, or which raises a given element of GF(2m)} to a given power. A matrix (called a connection matrix) is derived from a primitive polynomial and is corresponded to a particular shiftregister. The nth power of the matrix corresponds to the shiftregister which multiplies by Xn. Examples are presented to illustrate the application of the technique
Unconventional superconductivity and antiferromagnetic quantum critical behavior in the isovalent-doped BaFe2(As1-xPx)2
Spin dynamics evolution of BaFe(AsP) was probed as a
function of P concentration via P NMR. Our NMR study reveals that
two-dimensional antiferromagnetic (AF) fluctuations are notably enhanced with
little change in static susceptibility on approaching the AF phase from the
superconducting dome. Moreover, magnetically ordered temperature
deduced from the relaxation rate vanishes at optimal doping. These results
provide clear-cut evidence for a quantum-critical point (QCP), suggesting that
the AF fluctuations associated with the QCP play a central role in the
high- superconductivity.Comment: 5 pages, 3 figure
Divergent nematic susceptibility in an iron arsenide superconductor
Within the Landau paradigm of continuous phase transitions, ordered states of
matter are characterized by a broken symmetry. Although the broken symmetry is
usually evident, determining the driving force behind the phase transition is
often a more subtle matter due to coupling between otherwise distinct order
parameters. In this paper we show how measurement of the divergent nematic
susceptibility of an iron pnictide superconductor unambiguously distinguishes
an electronic nematic phase transition from a simple ferroelastic distortion.
These measurements also reveal an electronic nematic quantum phase transition
at the composition with optimal superconducting transition temperature.Comment: 8 pages, 8 figure
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
Low temperature specific heat of La_{3}Pd_{4}Ge_{4} with U_{3}Ni_{4}Si_{4}-type structure
Low temperature specific heat has been investigated in a novel ternary
superconductor La_{3}Pd_{4}Ge_{4} with an U_{3}Ni_{4}Si_{4}-type structure
consisting of the alternating BaAl_{4} (ThCr_{2}Si_{2})- and AlB-type
layers. A comparative study with the related ThCr_{2}Si_{2}-type superconductor
LaPd_{2}Ge_{2}, one of the layers in La_{3}Pd_{4}Ge_{4}, is also presented.
From the normal state specific heat, the Sommerfeld coefficient mJ/mol K^2 and the Debye temperature = 256 K are derived
for the La_{3}Pd_{4}Ge_{4}, while those for the LaPd_{2}Ge_{2} are mJ/mol K^2 and = 291 K. The La_{3}Pd_{4}Ge_{4} has
moderately high electronic density of state at the Fermi level. Electronic
contribution on the specific heat, , in each compound is well
described by the BCS behavior, suggesting that both of the La_{3}Pd_{4}Ge_{4}
and the LaPd_{2}Ge_{2} have fully opened isotropic gap in the superconducting
state
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