A correlation between magnetic hysteresis [measured with a vibrating-sample magnetometer (VSM)] and defect structures (studied by transmission-electron microscopy) is reported for number of ${\mathrm{Bi}}_{2}$${\mathrm{Sr}}_{2}$${\mathrm{CaCu}}_{2}$${\mathrm{O}}_{\mathit{y}}$ single crystals in the as-grown state after annealing oxygen or vacuum above 400 \ifmmode^\circ\else\textdegree\fi{}C. Different regimes flux pinning can be distinguished from VSM measurements, which we associated point...

The heat capacity of niobium at constant magnetic induction has been measured in the immediate neighborhood ${T}_{c}(B)$ with millikelvin temperature resolution. An enhanced attributable to fluctuations is observed both above and below ${T}_{c}(B)$. dependence throughout transition region can be described over a wide range by universal curve scale uniquely determined thermodynamic parameters.

The electrodynamic properties of the quasi-two-dimensional heavy fermion superconductor CeCoIn5 have been investigated by microwave surface impedance measurements over a wide range frequencies and temperatures. We derive value penetration depth lambda(0) approximately 190 nm, with strong linear term in temperature dependence lambda(T) below T(c)/3, consistent superconducting gap line nodes. real part conductivity displays broad peak at low temperatures decreased scattering rate almost 2...

A recently discovered rare-earth copper-oxide material, which is superconducting above the temperature of liquid nitrogen, used to fabricate a high-efficiency electrically short dipole antenna. Thus necessity cool lead antenna structure helium temperatures avoided. Results are presented show gain enhancement achieved using this new material when compared with conventional copper at room temperature.

A theoretical analysis of the large-amplitude free vibration a damped elastic string shows that perturbation in vibrational frequency and precession any orbital motion about its equilibrium position resulting from nonlinearity is simply related to mean-square radius area motion. computer simulation coupled nonlinear equations measurements made on loosely stretched confirm our predictions, which differ those an earlier by Anand [J. Acoust. Soc. Am. 45, 1089–1096 (1969)]. The significance...

A generic physical model for the vibro-acoustic modes of violin is described treating body shell as a shallow, thin-walled, guitar-shaped, box structure with doubly arched top and back plates. comsol finite element, structure, software used to identify understand vibrational simply modeled violin. This identifies relationship between freely supported plate when coupled together by ribs assembled shell. Such coupling results in relatively small number eigenmodes or component modes, which...

As the first step toward developing a generic model for acoustically radiating vibrational modes of violin and related instruments, both freely supported edge-constrained top back plates have been investigated as functions shape, arching height, elastic anisotropy, f-holes associated island area, thickness graduations, additional boundary constraints ribs, soundpost, bass-bar present in assembled instrument. Comsol shell structure finite element software has used quasi-experimental tool,...

Abstract In this note we report some preliminary experimental results that are concerned with the way in which flux can move a superconductor of second type when magnetization curve is reversible (an 'ideal' specimen). We shall accept view, for there now much evidence (see, e.g. Bon Mardion et al. 1962, Kinsel 1962), penetration into II takes place through presence quantized 'Abrikosov vortices' superconducting electron fluid (Abrikosov 1957). also make reasonable assumption an ideal...

The normal and superconducting state c-axis transport properties of ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}{\mathrm{CaCu}}_{2}{\mathrm{O}}_{8}$ single crystals have been measured as a function doping magnetic fields parallel perpendicular to the ${\mathrm{CuO}}_{2}$ planes, using mesa structures containing small number atomic unit-cell layers. For low current bias, peak in magnetic-field-dependent resistance is observed scale approximately inversely with zero-field critical current. ${I}_{c}$...

Cohn Humphreys criticizes the UK superconductivity community for its apparent lack of positive response to recommendation by materials panel in UK's Technology Foresight exercise that additional funding should be directed towards processing superconductors applications (August p15). Be assured is totally convinced importance processing. The problem such a programme, compounded demise advanced technology programmes Department Trade and Industry (DTI), disbanding National Committee...

Microwave penetration and losses are derived for the anisotropic normal superconducting states of single crystals in shape thin platelets oriented parallel perpendicular to oscillating electromagnetic field. For platelet with microwave field major flat faces, large anisotropy state can result dissipation dominated by through edges rather than across main faces. The influence extreme is also considered account an anomalous peak loss below ${\mathit{T}}_{\mathit{c}}$ sometimes observed...

A wide-band cryogenic amplifier measurement system for time-resolved four-point IV-characteristic measurements on 2212-BSCCO mesa structures is described. We present which demonstrate the importance of self-heating 50 ns time scales. Such heating likely to have been very significant in many previously published measurements, where reported nonlinear IV characteristics used derive superconducting energy gaps.

The specific heat, C p , has been measured with high precision in a mono-crystal of YBa 2 Cu 3 O 7−δ (YBCO) superconductor the temperature range 55K-300K. measurements provide data relative resolution Δ / approximately 5 · 10 −4 . main conclusions are: 1) Close to superconducting transition heat shows influence fluctuations. 2) A reversible second order or weakly first phase is found occur at T o = 229 K

We present coplanar resonator measurements of the nonlinear microwave surface impedance laser ablated and electron-beam coevaporated YBa2Cu3O7−δ thin films at 8 GHz in zero applied magnetic fields, including effects irradiation with heavy ions. Correlations between changes resistance reactance as a function current suggest that there are different contributions to behavior low high currents both fields. In field, we microwave-induced flux lines responsible for observed behavior, resulting...

Measurements of the complex microwave surface impedance ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7}$ (YBCO) thin films in a coplanar resonator geometry are reported for number as function temperature and field at 8 16 GHz. Values derived dependence Labusch pinning parameter ${\ensuremath{\kappa}}_{p}$ \ensuremath{\eta}, which consistent with an independent flux-line model only weak interflux-line interactions. The observation losses mixed state scaling...

Measurements of the V-I characteristics and critical currents along c axis are reported for a number small single crystals ${\mathrm{Bi}}_{2}$${\mathrm{Sr}}_{2}$${\mathrm{CaCu}}_{2}$${\mathrm{O}}_{8+\mathrm{\ensuremath{\delta}}}$ as function temperature, magnetic field, oxygen stoichiometry. The primary aim this investigation was to investigate changes in c-axis resistivity resulting from misalignment pancake vortices across superconducting ${\mathrm{CuO}}_{2}$ planes at melting 3D-2D...