Neutron irradiation studies on Y-123 thick films deposited by liquid phase epitaxy on single crystalline substrates

Vostner, A.; Sun, Yipeng; Weber, H.W.; Cheng, Y.; Kuršumović, A.; Evetts, J.E.

doi:10.1016/s0921-4534(03)01299-1

Cited by 9 publications

(6 citation statements)

References 25 publications

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“…But here they use an extremely high electric field criterion of 50 mV cm À 1 , and the apparent enhancement could simply be caused by a reduction in n-value due to irradiation. Later neutron irradiation studies [48][49][50] on epitaxial YBCO films, reported only a detrimental effect on J c (sf) while lifting in-field performance. On the basis of this, we feel it still remains to be confirmed that pinning centres created by irradiation can improve J c (sf).…”

Section: Resultsmentioning

confidence: 99%

Universal self-field critical current for thin-film superconductors

2015

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For any practical superconductor the magnitude of the critical current density, Jc, is crucially important. It sets the upper limit for current in the conductor. Usually Jc falls rapidly with increasing external magnetic field, but even in zero external field the current flowing in the conductor generates a self-field that limits Jc. Here we show for thin films of thickness less than the London penetration depth, λ, this limiting Jc adopts a universal value for all superconductors—metals, oxides, cuprates, pnictides, borocarbides and heavy Fermions. For type-I superconductors, it is Hc/λ where Hc is the thermodynamic critical field. But surprisingly for type-II superconductors, we find the self-field Jc is Hc1/λ where Hc1 is the lower critical field. Jc is thus fundamentally determined and this provides a simple means to extract absolute values of λ(T) and, from its temperature dependence, the symmetry and magnitude of the superconducting gap.

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Section: Resultsmentioning

confidence: 99%

Universal self-field critical current for thin-film superconductors

2015

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“…A major issue for fusion magnets is their response to neutron radiation. Additional artificial defects are generated in the superconductor during neutron irradiation, which may degrade the superconductor or result in pinning centers [3]. Therefore, the CCs were sequentially irradiated by neutrons up to the expected ITER life time fluence m and beyond.…”

Section: Introductionmentioning

confidence: 99%

YBCO Coated Conductors for Fusion Magnets

Fuger

Eisterer

Weber

2009

IEEE Trans. Appl. Supercond.

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Coated conductors (CCs) are considered as an alternative to low temperature superconductors in fusion magnets. High magnetic fields are needed to confine the plasma, which can be generated by YBCO coated conductors at relatively high temperatures (50-77 K). The critical current densities of CCs improved continuously during the last few years and the production was scaled up. The conductors will be exposed to neutron radiation in a fusion magnet, which could potentially improve or degrade their properties. Industrial YBCO coated conductors were characterized by magnetization and direct transport measurements in magnetic fields of up to 15 Tesla and at temperatures between 50 and 85 K. The critical current, its anisotropy and the irreversibility line were determined. The measurements were performed on different samples, which were sequentially irradiated up to a fluence of 2 10 22 m 2 (two times the ITER specification). The measurements were repeated after each irradiation step to investigate the change in the superconducting parameters. Depending on the production process of the CC and on the actual operation conditions, an increase or a decrease of the critical current density is observed. The measurements show that the performance of the CC nearly reaches the required specification for ITER conductors at present. Neutron irradiation generally does not degrade their properties in the operating range of fusion magnets.

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“…For this reason LPE films are commonly grown on a closely matched seed layer previously deposited by physical vapour deposition. Epitaxial YBCO films grown by LPE have a high degree of perfection and tend therefore to have a low critical current density, J c [17], although the critical current can be increased by introducing flux pinning defects, for instance by irradiation [18]. In contrast physical vapour deposition (PVD) and chemical vapour deposition (CVD) are commonly treated as high supersaturation growth processes (σ = 10-100) with a correspondingly small inter-step distance, [5,14,15].…”

Section: Introductionmentioning

confidence: 99%

Hybrid liquid phase epitaxy processes for YBa₂Cu₃O₇film growth

Kuršumović

Tomov

Hühne

et al. 2004

Supercond. Sci. Technol.

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A number of liquid phase epitaxy (LPE) related growth methods have been investigated. These hybrid-LPE processes enable high rate 'liquid assisted' growth of epitaxial YBa 2 Cu 3 O 7 films without the many disadvantages of classical LPE. Growth occurs by diffusive transport of Y through a thin liquid flux layer. This layer may be pre-deposited onto the substrate by various means including vacuum and non-vacuum techniques, or deposited at the growth temperature. The composition of the liquid layer is maintained during film growth by feeding YBa 2 Cu 3 O 7 , or the separate components, either from the vapour or by a powder route. Growth rates up to 10 nm s −1 have been demonstrated. Deposition of c-axis oriented epitaxial YBa 2 Cu 3 O 7 is reported on both seeded and non-seeded substrates; the process is tolerant of a high substrate mismatch. Films 1-2 µm thick with T c ∼ 90 K and a critical current density J c > 2 MA cm −2 have been grown on a range of single crystal substrates as well as on buffered textured metallic tapes. The mechanism of nucleation and growth from a thin liquid layer is described within the general theoretical framework of crystal growth. Particular features of the growth are the short time constant for equilibration of transients in the deposition conditions, the wide range of relative supersaturation spanned by the process, and dominance of interface kinetic effects compared to volume diffusion in the liquid flux.

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Neutron irradiation studies on Y-123 thick films deposited by liquid phase epitaxy on single crystalline substrates

Cited by 9 publications

References 25 publications

Universal self-field critical current for thin-film superconductors

Universal self-field critical current for thin-film superconductors

YBCO Coated Conductors for Fusion Magnets

Hybrid liquid phase epitaxy processes for YBa₂Cu₃O₇film growth

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Neutron irradiation studies on Y-123 thick films deposited by liquid phase epitaxy on single crystalline substrates

Cited by 9 publications

References 25 publications

Universal self-field critical current for thin-film superconductors

Universal self-field critical current for thin-film superconductors

YBCO Coated Conductors for Fusion Magnets

Hybrid liquid phase epitaxy processes for YBa2Cu3O7film growth

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Product

Resources

About

Hybrid liquid phase epitaxy processes for YBa₂Cu₃O₇film growth