Abstract
In this thesis, we studied the transport properties of Bi-2201 single crystals of two different compositions, Bi2.22Sr1.78CuOy and Bi2.3Sr1.7CuOy. Both single crystals were grown by the traveling solvent floating zone technique (TSFZ). The superconducting transition of the as-grown Bi2.22Sr1.78CuOy single crystal is about 6 K, and then it can be raised to 13 K after post annealing. The as-grown Bi2.3Sr1.7CuOy single crystal is nonsuperconducting, and has onset transition temperature about 13.5 K for 40 hours annealing time. The lower disorder parameter shows that there is a strong disorder effect in our samples.The temperature dependence of in-plane and out-of-plane resistivity with different magnetic fields were measured. Our result clearly demonstrates that the onset Tc almost shifts down with magnetic fields. The behavior is very different from other high-Tc copper oxide superconductor, and is more similar to the conventional low temperature superconductors. The temperature dependence of critical field Hc2 shows a upward curvature behavior, which is also different from other high-Tc cuprates. The temperature dependence of Hall angle obeys the power law with alpha =1.47~1.65, substantially lower than 2 as observed for most high Tc superconducting oxide such as YBa2Cu3O7. The value of increases with decreasing carrier concentration.The in-plane resistivity for both samples also show lnT dependence at low temperature, where can be fitted by 2-D weak localization theory. We have demonstrate that the lnT dependence of Hall coefficient, it implicates that the electron-electron interaction is important in our samples. But the magnetoresistance of our samples show it apparently contradict to theory of very weak magnetic field dependence, for magnetic field up to 16 tesla. The reason is still unclear.To compare with single CuO2 layer systems, such as Bi-2201, Tl-2201 and La2-xSrxCuO4, Bi-2201 system has the lowest transition temperature. The nonstoichiometry and excess oxygen atoms can induce strong disorder to suppress transition temperature. It may be the key reason why Bi-2201 has lower transition temperature in those systems.However, there are some anomalous behaviors, such as the linear variation of Tc in magnetic fields, the upward curvature of critical field and Hall angle, which is very different from other high-Tc copper oxide superconductors. Is Bi-2201 d-wave symmetry, so far the question is not answered. The pairing mechanism of Bi-2201 is worth further study.