Spray deposited Tl-Ba-Ca-Cu-O films and bulks subjected to a common anneal

Jergel, M.; Hanic, F.; Plesch, G.; Štrbı́k, V.; Liday, Jozef; Guajado, C F; Puente, Gerardo Silverio Contreras

doi:10.1088/0953-2048/7/12/009

Cited by 21 publications

(6 citation statements)

References 27 publications

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“…To minimize problems of Tl evaporation, a closed system represented by the powder-in-tube (PIT) method is used. It is important to stress that in both types of syntheses the resulting phase composition may differ, sometimes even substantially, from the initial chemical composition as confirmed by experiment [6].…”

Section: Phase Stability and Phase Diagramsmentioning

confidence: 84%

“…Tl-Ba-Ca-Cu-O powder was employed by Su et al [54]. The same authors also used the 2212 composition in a pellet form [51] whilst in our work we have used 2223 pellets to prepare Tl-2212 spray deposited films [6] and Venturini et al [55] applied 1223 pellets for thallination of Tl-1223 films. The advantage of using pellet Tl-sources lies in being able to keep pTl 2 O constant to a greater degree during sample sintering than in the case when either pure Tl 2 O 3 or Tl-based powder is applied.…”

Section: Single-zone Reaction Chambermentioning

confidence: 88%

“…In this type of reactor, the precursor and the source of thallium vapour are kept at the same temperature either in contact or in close proximity to one another and in a relatively closed space enabling the induction of an appropriate pTl 2 O. Alumina crucibles are usually used, closed to some extent and placed in an annealing atmosphere of p0 2 which might also contain other gases [6,50]. The precursor and thallium source are then heated together to a temperature necessary for solid-state sintering or partial melting of this all-component compound.…”

Section: Single-zone Reaction Chambermentioning

confidence: 99%

“…For this purpose, thermogravimetric (TG, DTG) and DTA measurements must be performed for each particular nitrate mixture used. Results of such a measurement for homogenized solid nitrate mixtures with a cation ratio of Ba:Ca:Cu = 2:2.3:3 are demonstrated in figure 14, from which one can see that the nitrate decomposition is over at about 800 • C [6]. For practical applications the use of poly-crystalline substrates is of a great importance.…”

Section: Deposition From Aerosolmentioning

confidence: 99%

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Tl-based superconductors for high-current, high-field applications

Jergel

Conde-Gallardo

Falcony

et al. 1996

Supercond. Sci. Technol.

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We have reviewed the convenience and possibility of utilizing thallium-based HT c superconductors for power applications. Some basic properties of Tl-based systems such as the crystal structure, phase stability, weak-links, pinning problems and irreversibility lines are discussed first. Two basic approaches to conductor preparation are then described, the closed and the open one. Special attention is focused on the fabrication of Tl-1223 and Tl-2223 superconductors. In the case of the more successful open approach a two-step technological procedure is usually chosen: first, the basic precursor material without Tl is synthesized, then second, the precursor is thallinated in a one-or two-zone reaction chamber. The most important precursor preparation techniques are described including aerosol deposition from either solution or ink, electro-deposition, sol-gel methods such as spin-and dip-coating and screen-printing and painting. Finally, some properties of the produced conductors important for power applications are presented.

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Section: Phase Stability and Phase Diagramsmentioning

confidence: 84%

Section: Single-zone Reaction Chambermentioning

confidence: 88%

Section: Single-zone Reaction Chambermentioning

confidence: 99%

Section: Deposition From Aerosolmentioning

confidence: 99%

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Tl-based superconductors for high-current, high-field applications

Jergel

Conde-Gallardo

Falcony

et al. 1996

Supercond. Sci. Technol.

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“…The spray-pyrolysis technique is well suited for the preparation of large coatings with a potential for practical use. Its application for the synthesis of Tl-based superconducting films has been reported [6,7]. While the Tl-2212 phase usually forms very quickly, Tl-2223 is formed in the transformation reaction Tl-2212 → Tl-2223.…”

Section: Introductionmentioning

confidence: 99%

Tl-based superconducting films prepared by aerosol spray deposition and thallinated in an open system

et al. 2007

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Superconducting Tl-based films were prepared on a LaAlO 3 single crystal substrate. Spray pyrolysis of Ba, Ca and Cu nitrate solutions was used for deposition of the precursor films. They were subsequently ex-situ thallinated in flowing oxygen (open system). While the superconducting Tl-2212 phase formed at an annealing temperature of 880• C, thallination at 900• C led to the formation of a Tl-2223 / Tl-2212 mixture. The amount of Tl-2223 increased with prolonged thallination, whereas the Tl-2212 phase progressively disappeared. Films prepared in such a manner were c−oriented and contained only low amounts of non-superconducting impurities. The resulting samples were characterized by XRD and SEM and their T C values were determined by resistive four-point measurements. They showed critical temperatures in the range of T ON = 125-135 K, T C0 = 91 -93 K. Differences between the composition and properties of the obtained films and those thallinated in closed systems under 50 kPa of oxygen are discussed in this paper. Results show that the Tl-2212 → Tl-2223 transformation proceeds at a slower rate under flowing oxygen than in a closed system.

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