相关论文: A Structural Parameter for High Tc Superconductivi…
A new parameter named PESATc (Parametro Estructural de los Superconductores de Alta Temperatura critica) is presented and used to discuss an aproach to the 'Stripe Phases' in (La,Ca)MnO3 superconductors. The PESATc parameter is based on the…
Systematic microwave surface impedance measurements of YBCO single crystals grown in $BaZrO_3$ crucibles reveal new properties that are not directly seen in similar measurements of other YBCO samples. Two key observations obtained from…
A simple empirical relation has been found to exist between optimum Tc and the formal mean cation charge <qc> of perovskite-related superconductors, covering both conventional superconductors and superconducting cuprates. Tc is shown to…
Superconductivity is observed with critical temperatures near 9K in the tetragonal compound Mo5PB2. This material adopts the Cr5B3 structure type common to supercondcuting Nb5Si3-xBx, Mo5SiB2, and W5SiB2, which have critical temperatures of…
The La2-xPrxCayBa2Cu4+yOz (LaPrCaBCO) mixed oxides have been studied for their structural and superconducting properties using X-ray diffraction (XRD), d. c. resistivity, d. c. susceptibility and iodometric double titration. All the…
A material called LK-99, a modified-lead apatite crystal structure with the composition Pb$_{10-x}$Cu$_x$(PO$_4$)$_6$O ($0.9<x<1.1$), has been synthesized using the solid-state method. The material exhibits the Ohmic metal characteristic of…
The crystal structure of Pb$_{10}$(PO$_4$)$_6$O, the proposed matrix for the potential room-temperature superconductor LK-99, Pb$_{10-x}$Cu$_x$(PO$_4$)$_6$O ($x = 0.9-1.0$), has been reinvestigated by single-crystal X-ray diffraction using…
A new superconductor (Na0.25K0.45)Ba3Bi4O12, having an A-site-ordered double perovskite structure, with a maximum Tc ~ 27 K has very recently been discovered through hydrothermal synthesis at 593 K. The structural, elastic, electronic, and…
To distinguish between the effects of strain and magnetism on the superconductivity in $c$-axis La$_{2/3}$Ca$_{1/3}$MnO$_3$/YBa$_2$Cu$_3$O$_{7-\delta}$ (LCMO/YBCO) heterostructures, we study perovskite/YBCO/perovskite thin films using…
The crystal structure and superconductivity of hexagonal BaPtAs are reported. Single-crystal X-ray diffraction, magnetization, electrical resistivity, and specific heat measurements were performed in this study. Two hexagonal structures…
Bulk samples of TbFeAsO$_{0.9}$F$_{0.1}$ (T$_{c}$(on) = 50K) were measured by point contact Andreev reflection spectroscopy. The spectra show unambiguous evidence for multiple gap-like features plus the presence of high bias shoulders. By…
The structure and physical properties of superconducting compounds Y(La)-Ba(Sr)-Cu-O are studied, the compounds being prepared by the method of cryogenic dispersion of a charge consisting of premix oxides and carbonates. Electrical…
The (Cu)13-BEC model of high-temperature superconductivity was previously shown to account for many of the principal thermodynamic and electronic properties of the superconducting cuprates. Here I show that this model is also able to…
The La-2125 type La2-xDyxCa2xBa2Cu4+2xOz (0.1 < x < 0.5; LDBO) compounds have been synthesized and studied for their structural and superconducting properties by room temperature neutron diffraction, high field dc magnetization, four-probe…
The discovery of high temperature superconductivity in cuprates was possible only through an intimate knowledge of perovskite oxides which have been synthesized and characterized for decades at the IBM in the Z\"urich laboratoty. Especially…
The empirical relation of T_co(K)=2740/<q>_c^4 between the transition temperature of optimum doped superconductors T_co and the mean cationic charge <q>_c, a physical paradox, can be recast to strongly support fractal theories of high-T_c…
We observed superconductivity ($T_{c}$ $\simeq$2-3 K) in Li$_{x}$RhB$_{y}$ intermetallics wherein $x$ and $y$ vary over a wide compositional range. The crystal structure consists of cubic unit-cell ($a$ $\simeq$ 12.1 \AA ) with…
New features are reported in precision measurements of the complex microwave conductivity of high quality $YBa_{2}Cu_{3}O_{6.95}$ crystals grown in $BaZrO_{3}$ crucibles. A third peak in the normal conductivity, $\sigma_{1}(T)$, at around…
The recent surprising discovery of superconductivity with critical temperature $T_c$ = 32 K in MoB$_2$ above 70 GPa has led to the search for related materials that may superconduct at similarly high $T_c$ values and lower pressures. We…
Most of the novel superconductors are uniaxial crystals, with metallic planes ($ab$) orthogonal to an insulating axis ($c$). Far-infrared measurements of the reflectivity $R_{ab} (\omega)$ provide valuable information on their low-energy…