Characteristics of Rare-Earth-Free Superconducting Thin Films
Superconducting Tl-Ca-Ba-Cu-0 thin films deposited by rf magnetron sputtering from Tl2Ca2Ba2Cu3Ox, Tl3Ca2Ba2Cu3Ox and Tl2Ca3Ba1Cu3Ox targets were investigated. After post-annealing, the composition of films prepared from the Tl2Ca2Ba2Cu3Ox target was closest to that of the high-T c phase in the targets used. A Tl-Ca-Ba-Cu-O film with zero resistivity at 116 K exhibited the critical current densities of ∼5.5 × 106 A/cm2 at 5.0 K and ∼1.5 × 106 A/cm2 at 50 K. The critical current densities of a randomly oriented Tl-Ca-Ba-Cu-0 film, ∼3.5 × 106 A/cm2 at 5.0 K and ∼8.0 × 105 A/cm2 at 50 K, were larger than those of a highly oriented Bi-Ca-Sr-Cu-O film, -1.1 × 106 A/cm2 at 4.5 K and ∼2.0 × 105 A/cm2 at 40 K. Both the films were comprised of the low-T c phase.
KeywordsCritical Current Density Zero Field Gold Foil Critical State Model Zero Resistivity
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- 7.H. Kuwahara, M. Nakao and A. Mizukami, 88 MRS International Meeting on Advanced Materials Symposium D, Proceedings (to be published).Google Scholar