[show abstract][hide abstract] ABSTRACT: In this report, we demonstrate the feasibility of applying a 250-nm focused x-ray beam to study a single crystalline NbSe(3) nanobelt under high-pressure conditions in a diamond anvil cell. With such a small probe, we not only resolved the distribution and morphology of each individual nanobelt in the x-ray fluorescence maps but also obtained the diffraction patterns from individual crystalline nanobelts with thicknesses of less than 50 nm. Single crystalline diffraction measurements on NbSe(3) nanobelts were performed at pressures up to 20 GPa.
The Review of scientific instruments 04/2011; 82(4):043903. · 1.52 Impact Factor
[show abstract][hide abstract] ABSTRACT: BSCCO (2212) whiskers were fabricated via a melt-quench-growth method and their morphology was characterized with scanning/transmission electron microscopy and atomic force microscopy. Four-probe magneto-transport measurements were conducted as a function of temperature and current. In low magnetic fields and currents, the resistance decreases monotonically and vanishes at a temperature of ˜ 80 K. However, at large currents and magnetic fields the resistance shows a non-monotonic dependence on temperature, even showing values that are higher than the normal state resistance for certain ranges of the parameters We attribute the observed behavior to the brick-wall morphology of the whiskers leading to a competition between normal and superconductive tunnelings that is known to take place in granular superconductive systems.
[show abstract][hide abstract] ABSTRACT: We investigated confinement effects on the resistive anisotropy of a superconducting niobium strip with a rectangular cross-section. When the strip's transverse dimensions are comparable to the superconducting coherence length, we find the angle dependent magentoresistances at a fixed temperature can be scaled as R(theta, H) = R(H /Hctheta) where Hctheta = Hc0 (cos^2theta+gamma-2sin^2theta)-1/2 is the angular dependent critical field, gamma = w/d is the width to thickness ratio of the strip, and Hc0 is the out-plane critical field at theta = 0 . Our results can be understood in terms of the anisotropic diamagnetic energy of a one-dimensional superconductor in a magnetic field.