Hall effect of as-grown oxygen-deficient ${\mathrm{YBa}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{\mathit{x}}$ thin films

The resistivity and Hall effect have been measured in a number of samples of as-grown, oxygen deficient, c-axis-oriented ${\mathrm{YBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_{\mathit{x}}$ thin films, both as a function of temperature and oxidation state. The temperature dependence of the longitudinal resistivity and Hall coefficient were generally similar to films prepared by ex-situ oxidation processes with the R-T and 1/${\mathit{R}}_{\mathit{H}}$-T characteristics nearly linear and cot${\mathrm{\theta }}_{\mathit{H}}$∝${\mathit{T}}^2$. Small deviations from these laws were investigated and a quadratic fit obtained for the resistivity data and a cubic fit for cot${\mathrm{\theta }}_{\mathit{H}}$ but with dominant linear and quadratic terms, respectively. From the empirical data, expressions for the effective carrier relaxation times and mobilities were obtained and compared with other possible scattering mechanisms. In contrast to films reoxidized after growth, we find that for the as-grown films the Hall mobility ${\mathrm{\mu }}_{\mathit{H}}$ increases sharply and cot${\mathrm{\theta }}_{\mathit{H}}$ decreases with increasing oxygen content. This is discussed in terms of different oxidation conditions that lead to different lattice defects for the two cases.