We measured isofield magnetization curves as a function of temperature in two single crystal deoxygenated YBaCuO with T_c = 52 and 41.5 K. Isofield MvsT were obtained for fields running from 0.05 to 4 kOe. The reversible region the was analyzed terms scaling proposed by Prange, but searching best exponent $\upsilon$. analysis carried out each data sample set $\upsilon$=0.669, which corresponds 3D-xy exponent, did not produced collapsing when applied lowest fields. resulting Y123 K, shows...

The intergrain critical-current-density (${\mathit{J}}_{\mathit{c}\mathit{i}}$) distribution and intergranular volume fraction of ceramic superconductors were determined from ac-susceptibility measurements. sample was melt-treated polycrystalline (Tl,Pb)(Ba,Sr${)}_{2}$${\mathrm{Ca}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{\mathit{y}}$ [Tl (1:2:2:3)] high-${\mathit{T}}_{\mathit{c}}$ (\ensuremath{\sim}119 K in zero field) superconductor for fields up to 80 Oe temperatures between 30...

We have performed a magnetic study of bulk metallic sample Nb with critical temperature $T_{c}=8.5$ K. Magnetization versus (M {\it vs} T) data obtained for fixed fields above 1 kOe show superconducting transition which becomes broader as the field is increased. The are interpreted in terms diamagnetic lowest Landau level (LLL) fluctuation theory. scaling analysis gives values $T_{c}(H)$ consistent $H_{c2}(T)$% . search universal 3D LLL behavior by comparing results and YBaCuO, but obtain no...

We discuss theoretically the properties of an electromechanical oscillating system whose operation is based upon cyclic conservative conversion between gravitational potential, kinetic and magnetic energies. The consists a superconducting coil subjected to constant external force fields. oscillates has induced in it rectified electrical current magnitude may reach hundreds amperes. design differs from that most conventional superconductor machines since motion linear (and practically...

High excitation magnetoluminescence investigations have been performed on cylindrical ${\mathrm{In}}_{0.53}$${\mathrm{Ga}}_{0.47}$As/InP quantum dots with different diameters down to 30 nm. The magnetic field oriented normal the disks enhances lateral confinement of carriers inside dots, and splits energy levels positive negative angular momenta due Zeeman-like interaction. This splitting depends linearly B, is independent disk size. increase quantization by field, other hand, strongly dot...

Taking as an example the case of BaTiO3 ferroelectric crystals inside Y1Ba2Cu3Ox matrix (1-2-3 compound) it is shown that properties such can generate extra flux pinning effect, in addition to expected due normal character inclusions. The calculations show additional force attainable depends strongly on spontaneous polarization and piezoelectric strain tensor components material.

The quantum confined Stark effect has been investigated in InGaAs/InP wires with widths down to 20 nm. were fabricated by electron beam lithography and wet chemical etching using titanium as mask material. By metalorganic vapor phase epitaxy overgrowth high efficiencies are achieved even for very narrow wire structures. We observe blue shifts the luminescence peak energy up meV due lateral quantization. After evaporating a semitransparent 50 Å thick gold Schottky contact we red of 25...

The alternating Fe–Mn layered structures of the compounds FeMnAs x P[Formula: see text] display properties which have been demonstrated experimentally as very promising far commercial applications magnetocaloric effect are concerned. However, theoretical literature on this and other families still adopts simple molecular-field models in description important statistical mechanical like entropy variation that accompanies applied isothermal magnetic field cycling, well temperature following...

H-Nb2 O5(Nb28 O70 ) is a semiconductor whose structure built of NbO6octahedra, which share corners and edges to form blocks parallel the basal acplane structure. One unit cell contains two 3 × 4 5 octahedra displaced by 1/2 b -axis spacing, besides one further Nb atom located in tetrahedrally coordinated sites along channels baxis. Such contain octahedral interstices are preferential for point defect segregation this The possibility using as framework obtaining oriented spin arrays has never...

A simple statistical treatment which assumes that vortices may be trapped and eliminated by a network of nonsuperconducting walls separating cells superconductor material in ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}$ is able to provide an explanation for (i) the essentially time-logarithmic decay magnetization at low temperatures; (ii) clear deviations from strict law high (iii) presence---or absence---of minimum plot relative...

We measured the magnetization $M$ of a twin-aligned single crystal $\mathrm{Y}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{x}$ (YBaCuO), with ${T}_{c}=91\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, as function temperature $T$ and magnetic field $H$, $H$ applied along $ab$ planes. Isothermal $M$-vs-$H$ $M$-vs-time curves were obtained parallel (\ensuremath{\Vert}) perpendicular (\ensuremath{\perp}) to twin boundary (TB) direction. exhibited two minima below...

Introductory electromagnetism courses usually start the exposition of Faraday's induction law discussing ordinary situation in which induced electromotive force arises due to motion a resistive circuit presence magnetic field. In this paper we extend discussion cover application perfectly conducting as well superconducting circuits rather than circuits. While work done by external agent is transformed into heat, quite different either or used accelerate charge carriers, and energy...

We discuss the properties of an electromechanical oscillator whose operation is based upon cyclic, quasi-conservative conversion between gravitational potential, kinetic, and magnetic energies. The system consists a strong-pinning type-II superconductor square loop subjected to constant external force fields. oscillates in upright position at frequency that can be tuned range 10-1000 Hz, has induced it rectified electrical current. emphasis this paper on evaluation major remaining sources...

The present paper is based upon the fact that if an object part of a highly stable oscillating system, it possible to obtain extremely precise measure for its mass in terms energy trapped rather than through ratio between force and acceleration, provided such can be properly measured. subject timely since there great interest Metrology on establishment new electronic standard kilogram. Our contribution effort includes both proposal alternative definition mass, as well description realistic...

Abstract By admitting that superconductors of the family RE-Ba-Cu-O have ferroelectric regions along twin planes first-order elastic interaction between such and magnetic flux lines is calculated. It shown a stable separation exists line lattice wall quite strong pinning interactions are possible provided parameters same order magnitude as in other perovskites.