相关论文: Scaling behavior of current- voltage characteristi…

DC voltage versus current measurements of superconductors in a magnetic field are widely interpreted to imply that a phase transition occurs into a state of zero resistance. We show that the widely-used scaling function approach has a…

Based on renormalization group arguments we establish that for a superconductor in the presence of a weak external magnetic field, $B$, the dependence on $B$ and the deviation from the critical temperature, $\tau$, of a thermodynamic…

Employing a broadband microwave reflection configuration, we have measured the complex surface impedance, $Z_S(\omega,T)$, of single crystal La$_{0.8}$Sr$_{0.2}$MnO$_3$, as a function of frequency (0.045-45 GHz) and temperature (250-325 K).…

The current-voltage ($I$-$V$) characteristics of break junctions of polycrystalline La$_{1.85}$Sr$_{0.15}$CuO$_4$, Y$_{0.75}$Lu$_{0.25}$Ba$_2$Cu$_3$O$_{7-\delta}$, Bi$_{1.8}$Pb$_{0.3}$Sr$_{1.9}$Ca$_2$Cu$_3$O$_x$ and composite…

Most measurements of critical current densities in YBa$_2$Cu$_3$O$_{7-\delta}$ thin films to date have been performed on films where the \textit{c}-axis is grown normal to the film surface. With such films, the analysis of the dependence of…

We present measurements of the vortex-state surface impedance, Z_s = R_s + i X_s, of a high quality, ortho-II-ordered single crystal of the cuprate high temperature superconductor YBa2Cu3O6.52 (T_c = 59K). Measurements have been made at…

We report the temperature dependence of transport and magnetic properties of La$_{1-x}$Ca$_x$VO$_3$ for x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5. The system exhibits an insulator-to-metal transition concomitant with an…

The anisotropy of the magnetic field dependence of the specific heat of YBa$_2$Cu$_3$O$_{7 - {\rm \delta}}$ can be used to identify different low-energy excitations, which include phonons, spin-$ \frac{1}{2}$ particles, and electronic…

A detailed investigation of the scaling relations recently proposed by [J. d'Albuquerque e Castro, D. Altbir, J. C. Retamal, and P. Vargas, Phys. Rev. Lett. 88, 237202 (2002)] to study the magnetic properties of nanoparticles is presented.…

In this work we present the study of the elastic properties of polycrystalline samples of superconducting YBa_2Cu_3O_7 prepared by the sol-gel method. The quality of all samples was checked by x-ray diffraction and scanning electronic…

The strong coupling of superconductivity to the orthorhombic distortion in YBa2Cu3O7-d makes possible an analysis of the superconducting fluctuations without the necessity of subtracting any background. The present high-resolution…

We report on current-voltage measurements of the zero-field normal-superconducting phase transition in thin films of Pr$_{2-x}$Ce$_x$CuO$_{4-y}$ as a function of doping. We find that the small size of the critical regime in these materials…

Angular-dependent magnetic torque measurements performed near the critical temperature on single crystals of HgBa_{2}CuO_{4+y}, La_{2-x}Sr{x}CuO_{4}, and YBa_{2}Cu_{3}O_{6.93} are scaled, following the 3D XY model, in order to determine the…

An unifying scenario for the critical behavior of YBa$_{2}$Cu$_{3}$O$_{7-\delta}$ (YBCO) and Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta}$ (BSCCO) is proposed. It is shown that both critical crossovers observed in these materials follow by…

The measurements of temperature dependence of AC magnetic susceptibility were used to study the influence of inhomogeneities on intragranular superconducting properties of YBa2Cu3-xMxOy (M=Fe,x=0.005; Al,x=0.01; Cr,x=0.01),…

We have studied the dynamic and static critical behavior of spin glass transition in insulating La$_{0.9}$Sr$_{0.1}$CoO$_3$ single crystal by ac susceptibility and dc magnetization measurements in the vicinity of its freezing temperature…

We present out-of-plane dielectric and magnetodielectric measurements of single crystallines $\alpha$-RuCl$_3$ with various degrees of stack faults. A frequency dependent, but field independent, dielectric anomaly appears at…

In extensive Monte Carlo simulations the phase transition of the random field Ising model in three dimensions is investigated. The values of the critical exponents are determined via finite size scaling. For a Gaussian distribution of the…

Single crystals of Cu$_{13}$Ba were successfully grown out of Ba-Cu self flux. Temperature dependent magnetization, $M(T)$, electrical resistivity, $\rho(T)$, and specific heat, $C_p(T)$, data are reported. Isothermal magnetization…

Using micro-bridge technique, we have studied the vortex dynamics in a very low temperature region (i.e. T/Tc -> 0) of the B-T phase diagram of Bi_2Sr_2Ca_1Cu_2O_{8+\delta} single crystal. We distinguish two types of vortex dynamics near…