The Influence of Oxygen Partial Pressure on Growth of the (Hg,Re)-1223 Intergrain Junction

Abstract

Hg 0 82 Re 0 18 Ba 2 Ca 2 Cu 3 O 8+ polycrystalline samples were successfully obtained by using different oxygen partial pressure in the annealing treatment of the precursor ceramic. The doping state was confirmed by X-ray powder diffraction pattern analysis and by observing distinct thermopower values at room temperature. Also, the intergrain regions have shown an improvement in the critical current density when using the precursor preparation with 10% O 2 and 90% Ar (optimal doped). The optimal doped sample has presented the highest exponent of the [1 () 2 ] dependence. For the case of (Hg,Re)-1223 polycrystalline superconductor applications, the exponent can be used as a junction quality parameter.Index Terms-Critical current density, high-, (Hg,Re)-1223 samples, thermoelectric power.

A Description of the Transport Critical Current Behavior of Polycrystalline Superconductors Under the Applied Magnetic Field

“…This function yields positive unilateral values and is always used to represent positive physical quantities. Furthermore, this Gamma distribution is the classical distribution used to describe the microstructure of granular samples [23] and reproduces the grain radius distribution in high-T c ceramic superconductors [24].…”

Enhancing LVRT of DFIG by Using a Superconducting Current Limiter on Rotor Circuit

“…Some materials, named superconductors, present the characteristic of null resistance under certain operational conditions, named critical temperature (T c ), critical current density (J c ) and critical magnetic field (H c ) ( Figure 5) [21]. Whenever one or more of such parameters increases above critical limits, the superconductor makes a transition from superconducting to normal state.…”

Development and test of a small resistive fault current limiting device based on Hg, Re-1223 and Sm-123 ceramics

“…The quartz tubes were sealed in a high vacuum of 3 × 10 -6 Torr. The average density of the pellet samples was ρ = 4.2(2) g/cm 3 [28,29] . All procedures have taken place inside a glove box filled with argon gas.…”

“…In order to improve the grain growth, the annealing time was changed to 72 h at 865°C, as compared to Sin et al 27 . All details of the synthesis processes and sample characterization were reported elsewhere [28][29][30] . Samples of SmBa 2 Cu 3 O 7-d were prepared by a solid-state reaction method using commercial oxide powders of Sm 2 O 3 (99.99% ), CuO (99.99%), and BaCO 3 (99.99%).…”

“…Prior to weighing and mixing, the oxides and carbonate powder were pre-annealed at 110°C for more than 24 h in air to release moisture. Then, the powders were weighed in a glove box, homogenized in an agate mortar for one hour, and put placed into alumina crucibles and calcined at 930°C for 40 hours in air 24,[27][28][29][30][31] . The obtained precursors were again homogenized, pressed into pellets (with the a diameter of 16 mm), sintered in a horizontal tube furnace in flowing oxygen (10 ml/min) at about approximately 1060°C for 72 h, then cooled to 520°C and, held at this temperature for 24 h, subsequently cooled in the furnace to room temperature 31 .…”