1,796 research outputs found
Specific-heat study for ferromagnetic and antiferromagnetic phases in SrRu_{1-x}Mn_xO3
Low-temperature electronic states in SrRu_{1-x}Mn_xO_3 for x <= 0.6 have been
investigated by means of specific-heat C_p measurements. We have found that a
jump anomaly observed in C_p at the ferromagnetic (FM) transition temperature
for SrRuO_3 changes into a broad peak by only 5% substitution of Mn for Ru.
With further doping Mn, the low-temperature electronic specific-heat
coefficient gamma is markedly reduced from the value at x=0 (33 mJ/K^2 mol), in
connection with the suppression of the FM phase as well as the enhancement of
the resistivity. For x >= 0.4, gamma approaches to ~ 5 mJ/K^2 mol or less,
where the antiferromagnetic order with an insulating feature in resistivity is
generated. We suggest from these results that both disorder and reconstruction
of the electronic states induced by doping Mn are coupled with the magnetic
ground states and transport properties.Comment: 4 pages, 2 figures, submitted to the proceedings of ICM2009
(Karlsruhe
Spin density distribution in a partially magnetized organic quantum magnet
Polarized neutron diffraction experiments on an organic magnetic material
reveal a highly skewed distribution of spin density within the magnetic
molecular unit. The very large magnitude of the observed effect is due to
quantum spin fluctuations. The data are in quantitative agreement with direct
diagonalization results for a model spin Hamiltonian, and provide insight on
the actual microscopic origin of the relevant exchange interactions.Comment: 5 pages 4 figure
<Advanced Energy Conversion Division> Nano Optical Science Research Section
3-1. Research Activities in 202
Interlayer magnetoresistance due to chiral soliton lattice formation in hexagonal chiral magnet CrNb3S6
We investigate the interlayer magnetoresistance (MR) along the chiral crystallographic axis in the hexagonal chiral magnet CrNb3S 6. In a region below the incommensurate-commensurate phase transition between the chiral soliton lattice and the forced ferromagnetic state, a negative MR is obtained in a wide range of temperature, while a small positive MR is found very close to the Curie temperature. Normalized data of the negative MR almost falls into a single curve and is well fitted by a theoretical equation of the soliton density, meaning that the origin of the MR is ascribed to the magnetic scattering of conduction electrons by a nonlinear, periodic, and countable array of magnetic soliton kinks. © 2013 American Physical Society
59Co Nuclear Quadrupole Resonance Studies of Superconducting and Non-superconducting Bilayer Water Intercalated Sodium Cobalt Oxides NaxCoO2.yH2O
We report 59Co nuclear quadrupole resonance (NQR) studies of bilayer water
intercalated sodium cobalt oxides NaxCoO2.yH2O (BLH) with the superconducting
transition temperatures, 2 K < T_c <= 4.6 K, as well as a magnetic BLH sample
without superconductivity. We obtained a magnetic phase diagram of T_c and the
magnetic ordering temperature T_M against the peak frequency nu_3 59Co NQR
transition I_z = +- 5/2 +-7/2 and found a dome shape superconducting phase.
The 59Co NQR spectrum of the non-superconducting BLH shows a broadening below
T_M without the critical divergence of 1/T_1 and 1/T_2, suggesting an
unconventional magnetic ordering. The degree of the enhancement of 1/T_1T at
low temperatures increases with the increase of nu_3 though the optimal
nu_3~12.30 MHz. In the NaxCoO2.yH2O system, the optimal-T_c superconductivity
emerges close to the magnetic instability. T_c is suppressed near the phase
boundary at nu_3~12.50 MHz, which is not a conventional magnetic quantum
critical point.Comment: 4 pages, 5 figure
The alternatively spliced fibronectin CS1 isoform regulates IL-17A levels and mechanical allodynia after peripheral nerve injury.
BackgroundMechanical pain hypersensitivity associated with physical trauma to peripheral nerve depends on T-helper (Th) cells expressing the algesic cytokine, interleukin (IL)-17A. Fibronectin (FN) isoform alternatively spliced within the IIICS region encoding the 25-residue-long connecting segment 1 (CS1) regulates T cell recruitment to the sites of inflammation. Herein, we analyzed the role of CS1-containing FN (FN-CS1) in IL-17A expression and pain after peripheral nerve damage.MethodsMass spectrometry, immunoblotting, and FN-CS1-specific immunofluorescence analyses were employed to examine FN expression after chronic constriction injury (CCI) in rat sciatic nerves. The acute intra-sciatic nerve injection of the synthetic CS1 peptide (a competitive inhibitor of the FN-CS1/α4 integrin binding) was used to elucidate the functional significance of FN-CS1 in mechanical and thermal pain hypersensitivity and IL-17A expression (by quantitative Taqman RT-PCR) after CCI. The CS1 peptide effects were analyzed in cultured primary Schwann cells, the major source of FN-CS1 in CCI nerves.ResultsFollowing CCI, FN expression in sciatic nerve increased with the dominant FN-CS1 deposition in endothelial cells, Schwann cells, and macrophages. Acute CS1 therapy attenuated mechanical allodynia (pain from innocuous stimulation) but not thermal hyperalgesia and reduced the levels of IL-17A expression in the injured nerve. CS1 peptide inhibited the LPS- or starvation-stimulated activation of the stress ERK/MAPK pathway in cultured Schwann cells.ConclusionsAfter physical trauma to the peripheral nerve, FN-CS1 contributes to mechanical pain hypersensitivity by increasing the number of IL-17A-expressing (presumably, Th17) cells. CS1 peptide therapy can be developed for pharmacological control of neuropathic pain
A search for massive neutral bosons in orthopositronium decay
We have searched for an exotic decay of orthopositronium into a single photon
and a short-lived neutral boson in the hitherto unexplored mass region above
900 , by noting that this decay is one of few remaining
candidates which could explain the discrepancy of the orthopositronium
decay-rate. A high-resolution measurement of the associated photon energy
spectrum was carried out with a germanium detector to search for a sharp peak
from this two-body decay. Our negative result provides the upper-limits
of\mbox{ } on the branching ratio of such a decay in the
mass region from 847 to 1013 , and excludes the
possibility of this decay mode explaining the discrepancy in the
orthopositronium decay-rate.Comment: a LaTeX file (text 7 pages) and a uuencoded gz-compressed PostScript
file (text 7 pages + figures 4 pages
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