Abstract:
The Bi2Sr2CaCu20g single crystal with a superconducting
transition temperature equal to 90 ± 2 K was prepared. The irreversibility
line of the single crystal for a mgnetic field direction along the c-axis and
T*
in the ab-plane was determined. The reduced temperature (l - T ) is
proportional to H 1.1 for fields below 004 T and proportional to HO.09 for
fields above 0.4 T. The zero temperature upper critical field Hc2(0) and
coherence length ~ (0) were determined from the magnetization
meaurements to be H-lC2=35.9T , H//C2=31.2T, ~c(0)=35.0 A, and
~ab(0)=32.5A,and from the magnetoresistance measurements to be H-lc2 =
134.6T , H//C2=55.5T '~c(0)=38.1 A, and ~ab(0)=2404 A for both
directions of the applied magnetic field. The results obtained for Hc2(0)
and ~(O) are not reliable due to the rounding that the single crystal exhibits
in the magnetization and magnetoresistance curves. The magnetization
relaxation of the single crystal was investigated, and was found to be
logarithmic in time, and the relaxation rate increases with temperature up
to 50 -60 K, then decreases at higher temperatures.
