Effect of γ-Irradiation on YBa2Cu3O7−x Ceramics and Monocrystals in the Superconducting State

Polyak, O.Yu.; Tukhvatulin, R.Kh.; Kim, Chan; Gasanov, É. M.; Ибрагимова, Э. М.

doi:10.1002/pssa.2211220151

Cited by 18 publications

(7 citation statements)

References 12 publications

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“…Irradiation experiments are effective methods for producing such defects in a rather controlled manner. The irradiation techniques commonly employed involve electrons [11], protons [12], γ rays [13][14][15], neutrons [16] and ions [17]. Of these, γ irradiation is one of the most efficient ways to create homogeneously distributed defects, because of the great penetration capability of γ rays over the whole material, creating localized defects that function as flux-pinning sites.…”

Section: Introductionmentioning

confidence: 99%

Microstructural study of samples irradiated with rays at high doses

Rangel

Galván²,

Adem

et al. 1998

Supercond. Sci. Technol.

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We have investigated the damage induced by irradiation in silver added samples. The samples were prepared with 0 and 6.5 wt% of silver and irradiated by high-energy irradiation (50-150 Mrad). The roles of silver and dosage irradiation are discussed in terms of their effects on microstructure, crystallinity, critical temperature and zero-resistance temperature . After irradiation, decreased while the room-temperature electrical resistance increased by a factor of 8 for some of the samples. The difference in between irradiated and non-irradiated YBCO samples was of the order of 10 K. We have found that the difference is bigger for silver-added samples. We have also observed several changes in diffraction patterns of YBCO and YBCO-silver samples. SEM images, EDS and XPS analysis showed that silver resided inside the grains as single atoms and as metallic clusters. The relative concentrations of the elements in samples were quantified by Auger electron spectroscopy. The values showed a gradual increase for radiation doses ranging between 0 and 100 Mrad. For doses up to 100 Mrad, decreased because of the weak-link breakage induced by high doses of rays.

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Section: Introductionmentioning

confidence: 99%

Microstructural study of samples irradiated with rays at high doses

Rangel

Galván²,

Adem

et al. 1998

Supercond. Sci. Technol.

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“…As observed, in samples without silver, the variation in T c is wider because the irradiation induces vacancies and provides oxygen mobility, presumably between O(4) and O(5) positions. As Polyak et al [15] point out, the difference in the sharpness of the superconducting transition width seems to be associated with the unstable radiation-stimulated ordering of the oxygen into the lattice in O(4) positions. In this sense, the lower T c values obtained for silver-added samples shown in the lower curve result because silver serves as an oxygen carrier and the irradiation acts on the silver and stimulates the incorporation of a high level of oxygen into the cell.…”

Section: Methodsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Methodological, applied and thermodynamic aspects of hydrogen sorption by graphite and related carbon nanostructures

Nechaev¹,

Alekseeva²

2004

Russ. Chem. Rev.

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We have investigated the damage induced by irradiation in Y 1 Ba 2 Cu 3 O 7−x silver added samples. The samples were prepared with 0 and 6.5 wt% of silver and irradiated by high-energy γ irradiation (50-150 Mrad). The roles of silver and dosage irradiation are discussed in terms of their effects on microstructure, crystallinity, critical temperature (T c ) and zero-resistance temperature (T 0 ). After irradiation, T c decreased while the room-temperature electrical resistance increased by a factor of 8 for some of the samples. The difference in T 0 between irradiated and non-irradiated YBCO samples was of the order of 10 K. We have found that the difference is bigger for silver-added samples. We have also observed several changes in diffraction patterns of YBCO and YBCO-silver samples. SEM images, EDS and XPS analysis showed that silver resided inside the grains as single atoms and as metallic clusters. The relative concentrations of the elements in samples were quantified by Auger electron spectroscopy. The J c values showed a gradual increase for radiation doses ranging between 0 and 100 Mrad. For doses up to 100 Mrad, J c decreased because of the weak-link breakage induced by high doses of γ rays.

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“…Some authors have observed an improvement of the superconducting properties with dose increment (Boiko et at., 1988;Leyva et al, 1992), some others report exactly the opposite (Vasek et al, 1989;Elkholy et al, 1996), and other studies have not found any dependence (Bohandy et al, 1987;Cooksey et al, 1994). These contradictions have not been completely explained yet; some authors even attribute these behaviors to a "sample effect" (Polyak et al, 1990). However, Belevtsev et al (Belevtsev et al, 2000) has determined the relationship between the superconducting order parameter 2 and the density of oxygen vacancy rate lower bound, expressed in displacement per atom, in order to achieve significant modification of the superconducting behavior.…”

Section: Introductionmentioning

confidence: 93%