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arXiv · 1005.4789

Temperature range of superconducting fluctuations above T_c in YBa_2Cu_3O_{7-δ} single crystals

M. S. Grbic·M. Pozek·D. Paar·V. Hinkov·M. Raichle·D. Haug·B. Keimer·N. Barisic·A. Dulcic
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Abstract

Microwave absorption measurements in magnetic fields from zero up to 16 T were used to determine the temperature range of superconducting fluctuations above the superconducting critical temperature T_c in YBa_2Cu_3O_{7-δ}. Measurements were performed on deeply underdoped, slightly underdoped, and overdoped single crystals. The temperature range of the superconducting fluctuations above T_c is determined by an experimental method which is free from arbitrary assumptions about subtracting the nonsuperconducting contributions to the total measured signal, and/or theoretical models to extract the unknown parameters. The superconducting fluctuations are detected in the ab-plane, and c-axis conductivity, by identifying the onset temperature T'. Within the sensitivity of the method, this fluctuation regime is found only within a fairly narrow region above T_c. Its width increases from 7 K in the overdoped sample (T_c = 89 K), to at most 23 K in the deeply underdoped sample (T_c = 57 K), so that T' falls well below the pseudogap temperature T*. Implications of these findings are discussed in the context of other experimental probes of superconducting fluctuations in the cuprates.

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M. S. Grbic, M. Pozek, D. Paar, V. Hinkov, M. Raichle, D. Haug, B. Keimer, N. Barisic, A. Dulcic. 2011-02-14. Temperature range of superconducting fluctuations above T_c in YBa_2Cu_3O_{7-δ} single crystals. https://doi.org/10.1103/physrevb.83.144508

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