Abstract
The apparentT c of some high temperature superconductors such as BiSrCaCuO and TlBaCaCuO measured by low (10–20,000 Hz) a.c. inductance techniques is shifted downward by up to 30K in the presence of modest (400 Oe) d.c. magnetic fields. Dc magnetization (SQUID) measurements of the same samples show no such shifts in the same magnetic fields. Other materials like YBaCuO and TlPbSrCaCuO do not show such shifts ofT c in a.c. inductance measurements in d.c. magnetic fields. While BiSrCaCuO and TlBaCaCuO are known to exhibit flux creep/flux flow phenomena resulting in low irreversibility line behaviour as measured by both a.c. and SQUID techniques, the aboveT c shift is apparently a new phenomenon. Materials exhibiting this property contain two or more layers of metal ions between the CuO conductance layers (2212, 2223 structure). Materials with only one metal ion layer between the CuO layers (123, 1223 structure) do not show the apparentT c shift, suggesting that the phenomenon is a result of the properties of magnetically-isolated CuO layers. Implications of the latter will be discussed.
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References
Dew-Hughes D 1988Cryogenics 28 674
Flippen R B and Askew T R 1988J. Appl. Phys. 64 5908
Flippen R B and Askew T R 1990J. Appl. Phys. (to be published)
Flippen R B and Subramanian M A 1990 (to be published)
Geballe T H and Hulm J K 1988Science 239 367
Ginsberg D (ed.) 1989Physical properties of high temperature superconductors (Teaneck, NJ: World Scientific) Ch. 3.
Malozemoff A P, Worthington T K, Yeshurun Y, Holtzberg F and Ke P H 1988Phys. Rev. B38 7203
Subramanian M Aet al 1988aPhysica C153–155 608
Subramanian M Aet al 1988bScience 239 1015
Van den Berg J, van der Beek C J, Kes P H, Mydosh J A, Menken M J V and Menovsky A A 1989Supercond. Sci. Technol. 1 249
Yeshurun Y, Malozemoff A P, Worthington T K, Yandrofski R M, Krusin-Elbaum L, Holtzberg F, Dinger T R and Chandrashekhar G V 1989Cryogenics 29 258
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Flippen, R.B. AC-measured shifts inT c of high temperature superconductors: The effect of interlayer structure. Bull. Mater. Sci. 14, 105–110 (1991). https://doi.org/10.1007/BF02747299
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DOI: https://doi.org/10.1007/BF02747299