Recent observation of anomalous superconducting behavior of ultrathin YBCO films and single crystals of cluster borides
We report the number of deviations from conventional behavior in superconducting properties of ultrathin (1–3 unit-cell (UC)) YBa₀₂Cu₃O₇₋x films sandwiched between semiconducting Pr₀,₆Y₀,₄Ba₂Cu₃O₇₋x layers and for single crystals of cluster superconductor: dodecaboride ZrB₁₂. We have found a qua...
Збережено в:
| Дата: | 2006 |
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| Автор: | |
| Формат: | Стаття |
| Мова: | English |
| Опубліковано: |
Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
2006
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| Назва видання: | Физика низких температур |
| Теми: | |
| Онлайн доступ: | http://dspace.nbuv.gov.ua/handle/123456789/120350 |
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| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Recent observation of anomalous superconducting behavior of ultrathin YBCO films and single crystals of cluster borides / V.A. Gasparov // Физика низких температур. — 2006. — Т. 32, № 8-9. — С. 1105–1114. — Бібліогр.: 33 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| Резюме: | We report the number of deviations from conventional behavior in superconducting properties
of ultrathin (1–3 unit-cell (UC)) YBa₀₂Cu₃O₇₋x films sandwiched between semiconducting
Pr₀,₆Y₀,₄Ba₂Cu₃O₇₋x layers and for single crystals of cluster superconductor: dodecaboride ZrB₁₂.
We have found a quadratic temperature dependence of the kinetic inductance, Lk⁻¹(Т)
, at low temperatures
independent of frequency, with a break in slope at TBKT
dc , the maximum of real part of
conductance, ωσ₁(T), and a large shift of the break temperature and the maximum position to
higher temperatures with increasing frequency ω. We obtain from these data the universal ratio
T /Lk⁻¹
(Tdc ) = 25, 25, and 17 nHK for 1-, 2- and 3-UC films, respectively in close agreement
with theoretical prediction for vortex—antivortex unbinding transition. Superfluid density of
ZrB₁₂ displays unconventional temperature dependence with pronounced shoulder at T/Tc equal
to 0.65. Contrary to conventional theories we found a linear temperature dependence of Hс₂(Т)
from Tc down to 0.35 K. We suggest that both λ(T) and Hс₂(Т) dependencies can be explained by a
two band BCS model with different superconducting gap and Tc. |
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