Critical current decay with ageing for polycrystalline YBCO wires and rings

Gherardi, Laura; Metra, P.; Vellego, G.; Radaelli, P. G.

doi:10.1016/0011-2275(90)90287-m

Cited by 10 publications

(2 citation statements)

References 4 publications

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“…For even longer storage periods, a marginal decrease in T c0 was found, accompanied by a small increase in the normal-state resistivity. The long-term stability of unirradiated thin YBCO films has long been a topic of controversial discussion, especially with regard to effects of exposure to humidity and carbon dioxide in air [44]. Exposure to air causes YBCO to form hydroxide and carbonate layers on its surface [45].…”

Section: Long-term Stability Of Nanopatterned Ybco Filmsmentioning

confidence: 99%

Temporal Evolution of Defects and Related Electric Properties in He-Irradiated YBa2Cu3O7−δ Thin Films

Keppert,

Aichner,

Rohringer

et al. 2024

IJMS

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Thin films of the superconductor YBa2Cu3O7−δ (YBCO) were modified by low-energy light-ion irradiation employing collimated or focused He+ beams, and the long-term stability of irradiation-induced defects was investigated. For films irradiated with collimated beams, the resistance was measured in situ during and after irradiation and analyzed using a phenomenological model. The formation and stability of irradiation-induced defects are highly influenced by temperature. Thermal annealing experiments conducted in an Ar atmosphere at various temperatures demonstrated a decrease in resistivity and allowed us to determine diffusion coefficients and the activation energy ΔE=(0.31±0.03) eV for diffusive oxygen rearrangement within the YBCO unit cell basal plane. Additionally, thin YBCO films, nanostructured by focused He+-beam irradiation into vortex pinning arrays, displayed significant commensurability effects in magnetic fields. Despite the strong modulation of defect densities in these pinning arrays, oxygen diffusion during room-temperature annealing over almost six years did not compromise the signatures of vortex matching, which remained precisely at their magnetic fields predicted by the pattern geometry. Moreover, the critical current increased substantially within the entire magnetic field range after long-term storage in dry air. These findings underscore the potential of ion irradiation in tailoring the superconducting properties of thin YBCO films.

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Section: Long-term Stability Of Nanopatterned Ybco Filmsmentioning

confidence: 99%

Temporal Evolution of Defects and Related Electric Properties in He-Irradiated YBa2Cu3O7−δ Thin Films

Keppert,

Aichner,

Rohringer

et al. 2024

IJMS

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“…For example, the irreversible strain tolerance, ε r (the strain level above which I c degrades irreversibly) of monolayer (Bi, Pb)-2223/Ag tapes is less than 0.2% [1][2][3], whereas it should withstand a strain of about 0.4% to meet working strain conditions [4]. The effect of mechanical strain on the transport properties of the tapes has been studied [1][2][3][5][6][7][8][9][10][11]. Also, approaches were made by several groups to improve the strain tolerance of the tapes by: introducing silver in different forms into the core [12][13][14][15]; making them in multifilamentary configurations [1,[16][17][18]; reinforcement of the sheath by metals or metal alloys [19,20]; or by making Ag alloy sheathed tapes [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Bend strain and tensile stress characteristics of (Bi, Pb)-2223/Ag-Cu alloy sheathed tapes

Aloysius

Sobha

Guruswamy

et al. 2001

Supercond. Sci. Technol.

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The dependence of Ic on the bend strain and tensile stress characteristics of (Bi, Pb)-2223/Ag-Cu alloy sheathed tapes with varying Cu composition in the sheath has been studied in both mono- and multifilamentary configurations. The irreversible stain (εr) and the critical stress (σc) were found to improve as the level of Cu doping in the sheath increases. εr and σc were found to be about twice as large for the 9 at% Cu doped sample in both mono- and multifilamentary cases compared to the corresponding pure samples. The multifilamentary tapes were found to endure more strains and stresses due to their fine filament structure and low fill factor of the superconductor core. The degradation of Ic above σc was found to be rapid, while that for strains above εr was gradual, retaining a significant amount of Ic even after high values of applied strain.

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