相关论文: Isotope Effect on the Superconducting Transition T…
The effect of Pr substitution on the superconductivity and interlayer coupling of Bi2212 system is investigated. Magnetic and transport measurements were performed for purposes of characterization. The superconducting transition temperature…
We report a complete analysis of the formal oxidation state of Co in NaxCoO2, in the interval 0.31<x<0.67. Iodometric titration and thermoelectric power confirm that a direct relationship between the Na content and the amount of Co 3 +…
Here, we report the synthesis and characterization of sulphur-substituted iron telluride i.e. FeTe1-xSx; (x = 0-30 %) system and study the impact of low temperature oxygen (O2) annealing as well. Rietveld analysis of room temperature x-ray…
The present work describes the theoretical analysis of isotope effect coefficient as a function of transition temperature in two orbital per site model Hamiltonian in iron based superconducting system. The expression of isotope effect…
A brief overview of changes in the superconducting transition temperature under pressure and evolution of specific heat capacity jump at Tc for two related families of iron - based superconductors, Ba{1-x}KxFe2As2 (0.2 < x < 1.0) and…
Anisotropic-gap and two-band effects smear out the superconducting transition (Tc) in literature reported thermal conductivity of MgB2, where large electronic contributions also suppress anomaly-manifestation in their negligible…
We have systematically studied the structural and physical properties of the superconducting hydrated Lix(H2O)yTaS2. The powder X-ray diffraction patterns suggest that all the samples are single-phase compounds, and the crystal structure is…
We have investigated the effect of oxygen isotope substitution on the metal-insulator transition temperature and the resistivity of the narrow band manganite (La0.25Pr0.75)0.7Ca0.3MnO3 in a constant magnetic field. A set of 16 samples…
Developing a theory of high-temperature superconductivity in copper oxides is one of the outstanding problems in physics. Twenty-five years after its discovery, no consensus on the microscopic theory has been reached despite tremendous…
We have measured the specific heat and magnetization {\it versus} temperature in a single crystal sample of superconducting La$_{2}$CuO$_{4.11}$ and in a sample of the same material after removing the excess oxygen, in magnetic fields up to…
The weak-coupling quantum phase diagrams of the one-dimensional (1D) Holstein-Hubbard and Peierls-Hubbard models are computed near half-filling, using a multi-step renormalization group technique. If strong enough, the electron-phonon…
We have investigated uniaxial and hydrostatic pressure effects on superconductivity in Fe1.07Te0.88S0.12 through magnetic-susceptibility measurements down to 1.8 K. The superconducting transition temperature Tc is enhanced by out-of-plane…
Two series of alpha and beta-NaxCoO2 materials have been prepared by means of Na deintercalation from the parent alpha-NaCoO2 and beta-Na0.6CoO2 phases, respectively. The alpha-NaxCoO2 materials undergo a…
The single electron tunneling spectroscopy on superconductor Na$_{x}$CoO$_2$$\cdot$ yH$_2$O and its starting compound Na$_{x}$CoO$_2$ has been studied with point-contact method. The spectra of Na$_{x}$CoO$_2$ have two types of distinct…
Various samples of sodium cobalt oxyhydrate with relatively large amounts of Na$^{+}$ ions were synthesized by a modified soft-chemical process in which a NaOH aqueous solution was added in the final step of the procedure. From these…
A wide variety of superconducting oxides are used to test a general model of high pressure induced transition temperature (T c) changes. The T c 's vary from a low of 24 K to a high of 164 K. Although the model is capable of predicting both…
The heat capacity of superconducting Na(x)CoO(2)*yH(2)O was measured and the data are discussed based on three different models: The thermodynamic Ginzburg-Landau model, the BCS theory, and a model including the effects of line nodes in the…
Ceramic samples of Sr2RuO(4-y)Sy (y=0.03-1.2) with intended isovalent substitution of oxygen by sulfur have been synthesized and explored in the temperature range 4-300K. It is found that at a range of optimum sulfur substitution the…
We report a study of oxygen isotope effects on low temperature specific heat, magnetization, and resistivity of La$_{1-x}$Ca$_{x}$MnO$_{3}$ and (La$_{1-y}$Pr$_{y})_{0.67}$Ca$_{0.33}$MnO$_{3}$. For the metallic compositions of…
The nonstoichiometric NaxCoO2 system exhibits extraordinary physical properties that correlate with temperature and Na concentration in its layered lattice without evident long-range structure modification when conventional crystallographic…