Ri. Khasanov et al., CROSSOVER FROM BULK PINNING TO GEOMETRICAL BARRIER IN A BI2SR2CACU2OXSINGLE-CRYSTAL AS REVEALED BY A SCANNING ESP PROBE METHOD, Physical review. B, Condensed matter, 54(18), 1996, pp. 13339-13342
The field distribution in the Bi:2212 rectangular strip, placed in a p
erpendicular magnetic field, was studied using the ESR microprobe scan
ned over the sample surface. The crossover of the magnetic-field profi
le from the dome shape, typical for a geometrical barrier (T>30 K), to
the bulk pinning picture (T<25 K), was observed upon variation of tem
perature. The analysis of field distribution made it possible to deter
mine the temperature dependence of the lower critical field.