6 research outputs found
Discovery of a new pulsating X-ray source with a 1549.1-s period, AX J183220-0840
A new pulsating X-ray source, AX J183220-0840, with a 1549.1-s period was
discovered at R.A.= 18h32m20s and Dec.=-8d40'30'' (J2000,
uncertainty=0.6degree) during an ASCA observation on the Galactic plane. The
source was observed two times, in 1997 and in 1999. A phase-averaged X-ray flux
of 1.1E-11 ergs cm-2 s-1 and pulsation period of 1549.1+/-0.4 s were
consistently obtained from these two observations. The X-ray spectrum was
represented by a flat absorbed power-law with a photon-index of =~0.8 and an
absorption column density of =~1.3E22 cm-2. Also, a signature of iron K-shell
line emission with a centroid of 6.7 keV and an equivalent width of
approximately 450 eV was detected. From the pulsation period and the iron-line
feature, AX J183220-0840 is likely to be a magnetic white dwarf binary with a
complexly absorbed thermal spectrum with a temperature of about 10 keV.Comment: 13 pages, 4 figures, accepted for publication in ApJ Letter
Superconductivity and physical properties of Ba24Si100 determined from electric transport, specific-heat capacity, and magnetic susceptibility measurements
Both Ba24Si100 and Ba24Ge100 with crystallographically identical structure are found to be superconducting at 1.4 and 0.27 K, respectively. Physical properties of this superconductor Ba24Si100 are studied by electric transport, specific heat capacity, and magnetic susceptibility measurements. The density of states at the Fermi level NEF=0.148 states eV-1(Siatom)-1 and a distinct jump of Cp at the superconducting transition temperature ΔCp=0.272JK-1mol-1 are obtained. An exponential fit of Cp below the superconducting states gives an energy gap 2Δ=0.423meV and shows that this is a superconductor having s-wave character or isotropic energy gap. On the basis of our experimental data other important physical parameters are also derived
Pressure Effect on Organic Conductors
Pressure is a powerful tool to unveil the profound nature of electronic properties in a variety of organic conductors. Starting from technology of high pressure, we plan to review what kind of physics or phenomena have previously been discussed
Superconductivity and physical properties of Ba24Si100 determined from electric transport, specific-heat capacity, and magnetic susceptibility measurements
Possible quantum Hall effect in a magnetic-field-induced phase transition in the quasi-one-dimensional CDW organic conductor, HMTSF–TCNQ
Uniaxial Strain Orientation Dependence of Superconducting Transition Temperature (<i>T</i><sub>c</sub>) and Critical Superconducting Pressure (<i>P</i><sub>c</sub>) in β-(BDA-TTP)<sub>2</sub>I<sub>3</sub>
Dependence of the superconducting transition temperature (<i>T</i><sub>c</sub>) and critial superconducting pressure (<i>P</i><sub>c</sub>) of the pressure-induced superconductor β-(BDA-TTP)<sub>2</sub>I<sub>3</sub> [BDA-TTP = 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene] on the orientation of uniaxial strain has been investigated. On the basis of the overlap between the upper and lower bands in the energy dispersion curve, the pressure orientation is thought to change the half-filled band to the quarter-filled one. The observed variations in <i>T</i><sub>c</sub> and <i>P</i><sub>c</sub> are explained by considering the degree of application of the pressure and the degree of contribution of the effective electronic correlation at uniaxial strains with different orientations parallel to the conducting donor layer