Upper critical magnetic fields of Bi2Sr2CuO6 single crystals

Magnetic phase diagram of the layered superconductor Bi2+xSr2−xCuO6+δ(Bi2201) withTc≈ 7 K

“…Our finding, roughly agrees with the suppression of superconductivity observed with a 50 kOe field found in Ref. [7] for a Bi2201 sample with T c ≈ 7 K. Similarly large values of H c2 (T ) (as the values found in Ref. [8]), were found in Ref.…”

“…The resulting Magnetic phase diagram of the layered superconductor Bi 2+x Sr 2−x CuO 6+δ (Bi2201) with T c ≈ 7 K3 mean field phase diagram shows a dH c2 /dT = −12 kOe/K, and a H c2 (0) ≈ 30 kOe, which reasonable agree with values obtained in Ref. [7] for a sample with similar T c and same field orientation. The value of H c2 (0) ≈ 60 kOe, estimated from the WHH formula [11], H c2 (0) = −0.69T c (dH c2 /dT ), is twice the value suggested by the phase diagram.…”

“…Regarding the anisotropy, a γ ≈ 3 were found in Refs. [7] and [8] while a much higher value γ ≈ 22 was found in Ref. [9].…”

“…For instance, values of H c2 (0) ≈ 60 kOe and dH c2 /dT = −16 kOe/K were found in Ref. [7] for H c-axis, while values about 3 times larger were found in Ref. [8] for the same quantities on a similar sample with same field orientation.…”

“…Among the studies presented in the literature for Bi2201, it is worth to cite the works of Refs. [7] and [8] which obtained magnetic phase diagrams trough resistivity measurements, and the work of Ref. [9] which studied fluctuation conductivity.…”