A study of the optimization of sputtering and sintering parameters for the growth of Tl2Ba2Ca2Cu3O10+χ superconducting films

Chrzanowski, J.; Burany, X.M.; Curzon, A.E.; Irwin, J. C.; Heinrich, B.; Fortier, N.; Cragg, A.

doi:10.1016/0921-4534(93)90419-q

Cited by 13 publications

(14 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The selection of the p(O 2 ) and T a parameters (P -T ) for the film thalliation was made by taking the stability line between the Tl-2212/Tl-2223 phases as a guide [9][10][11] (figure 1). Previous results [10,11] and observations with YBCO films [12] indicated that the best films in terms of T c and j c were grown in the vicinity of the phase stability line. Therefore we have explored T a = 820-870 • C and p(O 2 ) = 20-400 Torr with a thalliation time t a ranging from 5 to 40 min.…”

Section: Methodsmentioning

confidence: 99%

Characterization of films prepared by laser ablation of precursor targets andex situthalliation

Chrzanowski

Meng-Burany

Xing

et al. 1996

Supercond. Sci. Technol.

View full text Add to dashboard Cite

Thin films of Tl 2 Ba 2 CaCu 2 O 8 (Tl-2212) were grown on LaAlO 3 (001) single crystals by excimer laser ablation using Tl-free Ba 2 CaCu 2 O x targets and subsequent ex situ thalliation. The thalliation process of the film precursor (Ba 2 CaCu 2 O x ) took place in an Al 2 O 3 crucible containing the precursor and Tl-2212 powder. The procedure was carried out at a temperature T a = 820-870 • C and under a reduced oxygen pressure p(O 2 ) = 20-400 Torr. The resulting Tl-2212 films were characterized by XRD, AES, EDAX, ECP, Raman spectroscopy and a.c. susceptibility measurements. The films exhibited epitaxial, c-axis-oriented growth with critical temperatures T c = 98-106.5 K, transition widths T c = 0.5-1 K, and critical current densities at 77 K of j c = (1.2-3.5) × 10 6 A cm −2 . EDAX measurements showed that the films were as a rule somewhat Tl and Ba deficient but Ca rich (Tl 1.7 Ba 1.9 Ca 1.1 Cu 2 O 8 ). AES depth profiling revealed a noticeable depth dependence of the Ca and Ba distribution, though the combined concentration of these elements (Ba + Ca) was fairly constant throughout the whole film thickness. It is postulated that cation disorder (Ba Ca substitution) is responsible, at least in part, for the high critical current density observed in the Tl films. These point defects would contribute to the strong pinning of the flux lines in the films by creating a dense network of pinning centres.

show abstract

Section: Methodsmentioning

confidence: 99%

Characterization of films prepared by laser ablation of precursor targets andex situthalliation

Chrzanowski

Meng-Burany

Xing

et al. 1996

Supercond. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…In a conventional thalliation process, this means that Tl(2212) will be formed during heating to the thalliation temperature and must be transformed into Tl(2223) during the anneal [37,46,[50][51][52]. While Tl(2212) can be formed by a solid-state diffusion process [46,53], it has been suggested by many authors that the presence of a liquid phase is necessary for the Tl(2212) → Tl(2223) phase transformation [46,[53][54][55][56]. The transformation from Tl(2223) to Tl(1223) takes place by evaporation of Tl.…”

Section: Thermodynamic and Kinetic Factors Affecting Thalliationmentioning

confidence: 99%

Thallium-based HTS thin films, processing, properties and applications

Bramley¹,

O'connor²,

Grovenor³

1999

Supercond. Sci. Technol.

View full text Add to dashboard Cite

Thin films of the Tl-based high-temperature superconducting (HTS) phases are beginning to find application in a number of practical devices, especially in the field of microwave communication systems. This review describes the issues surrounding the fabrication of thin films of the thallium-based HTS materials. The influence of thermodynamics and kinetics, the various potential thalliation techniques and the selection of an appropriate substrate material are all important considerations when designing a process for the fabrication of thin films of these highly reactive materials. The properties of the resulting films are critically dependent on the microstructures developed during thalliation. Microstructural evolution during thalliation, the effect of structural defects on the properties of such films and the importance of achieving biaxial grain alignment in optimizing the properties of the films are all discussed.

show abstract

“…Using TlBaCaCuO powders, Ahn et al 51 have shown that the temperature at which Tl 2 Ba 2 Ca 2 Cu 3 O 10 forms decreases with decreasing oxygen partial pressure. 19,28,40 The effect of oxygen partial pressure was studied by carrying out the thallination step at atmospheric pressure in oxygen, air (19% O 2 ), 5% O 2 ͞Ar, and 1% O 2 ͞Ar atmospheres. 19,28,40 The effect of oxygen partial pressure was studied by carrying out the thallination step at atmospheric pressure in oxygen, air (19% O 2 ), 5% O 2 ͞Ar, and 1% O 2 ͞Ar atmospheres.…”

Section: Effect Of Oxygen Partial Pressure On the Phases Formedmentioning

confidence: 99%

“…These films have been prepared exclusively using ex situ postdeposition thallination processes, during which a precursor film is converted to the crystalline Tl 2 Ba 2 Ca 2 Cu 3 O 10 phase in the presence of a thallous oxide overpressure. 19,20,29,31,[33][34][35] A few studies have used a thallium oxide source held at a lower temperature than that of the film to maintain a thallous oxide overpressure. [34][35][36] The thallination step is most often carried out in the presence of a TlBaCaCuO powder, within a sealed gold pouch or ceramic ampoule, 21,[24][25][26][27][28] or within a closed, but unsealed, platinum or ceramic container.…”

Section: Introductionmentioning

confidence: 99%

Process optimization for the fabrication of Tl₂Ba₂Ca₂Cu₃O₁₀ thin films

Holstein

Parisi

1996

J. Mater. Res.

View full text Add to dashboard Cite

A process has been developed for the fabrication of nearly single phase superconducting Tl2Ba2Ca2Cu3O10 thin films on (100) LaAlO3 substrates with a superconducting transition temperature Tc of 120 K and low microwave surface resistance at temperatures up to 110 K. Amorphous BaCaCuO precursor films were first deposited by rf magnetron sputtering and then thallinated at elevated temperatures. The double TlO layer phases (Tl2Ba2Ca2Cu3O10 + Tl2Ba2CaCu2O8) formed preferentially over the single TlO layer phases (TlBa2Ca2Cu3O9 + TlBa2CaCu2O7) at high Tl2O partial pressures. Thin films containing Tl2Ba2Ca2Cu3O10 and a small amount of CuO were prepared from Cu-rich precursor films (Cu/Ba > 1.7), while lower Cu content led to the formation of Tl2Ba2CaCu2O8 as a secondary phase. Tl2Ba2Ca2Cu3O10 film epitaxy was enhanced by carrying out the thallination in reduced oxygen partial pressures of 0.01–0.05 atm. Following the thallination step, the Tl2Ba2Ca2Cu3O10 thin films had a superconducting transition temperature Tc of only 106 ± 4 K. An additional 62 h anneal at 800 °C or an 8 h anneal at 850 °C in a Tl2O/O2 atmosphere increased the Tc to 120 K. The increase in Tc was accompanied by a decrease in the c-axis lattice constant, an enhancement in the long-range order in the c-direction, and the formation of a small amount of Tl2Ba2CaCu2O8 as a secondary phase. Minimization of surface resistance at high temperature (95–110 K) requires that the fraction of Tl2Ba2CaCu2O8 secondary phase in the films be kept low. Process routes are also described for the formation of nearly single phase TlBa2Ca2Cu3O9 and TlBa2CaCu2O7 thin films and the formation of a new ordered intergrowth phase, Tl4Ba4Ca3Cu5O18, which consists of alternating Tl2Ba2CaCu2O8 and Tl2Ba2Ca2Cu3O10 layers.

show abstract

A study of the optimization of sputtering and sintering parameters for the growth of Tl2Ba2Ca2Cu3O10+χ superconducting films

Cited by 13 publications

References 29 publications

Characterization of films prepared by laser ablation of precursor targets andex situthalliation

Characterization of films prepared by laser ablation of precursor targets andex situthalliation

Thallium-based HTS thin films, processing, properties and applications

Process optimization for the fabrication of Tl₂Ba₂Ca₂Cu₃O₁₀ thin films

Contact Info

Product

Resources

About

A study of the optimization of sputtering and sintering parameters for the growth of Tl2Ba2Ca2Cu3O10+χ superconducting films

Cited by 13 publications

References 29 publications

Characterization of films prepared by laser ablation of precursor targets andex situthalliation

Characterization of films prepared by laser ablation of precursor targets andex situthalliation

Thallium-based HTS thin films, processing, properties and applications

Process optimization for the fabrication of Tl2Ba2Ca2Cu3O10 thin films

Contact Info

Product

Resources

About

Process optimization for the fabrication of Tl₂Ba₂Ca₂Cu₃O₁₀ thin films