Hall effect ofYBa2Cu3O7−δsingle crystals

For a number of ${\mathrm{YBa}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7\mathrm{-}\mathrm{\delta }}$ single crystals with various oxygen concentrations and differing values of the zero magnetic-field critical temperature $T_{c0\mathrm{}},$ the Hall effect has been investigated between 10 and 300 K by applying magnetic fields $\mathbf{H}\parallel c$ and currents $\mathbf{I}\perp c,$ where $c$ denotes the direction perpendicular to the Cu-O planes of this material. These measurements yield that the sign change of the Hall voltage close to $T_{c0\mathrm{}}$ varies with δ and eventually disappears in heavily oxygen-depleted ${\mathrm{YBa}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{7\mathrm{-}\mathrm{\delta }}$ single crystals. Such behavior can qualitatively be explained by a model calculation based on the time-dependent Ginsburg-Landau theory. In the normal state, we find that the Hall coefficient $R_H$ and the Hall angle ${\theta }_H$ vary as $R_H^{-1}\propto T$ and $\cot {\theta }_H\propto T^2$ in an extended temperature range, as has previously been found for fully oxygenated ${\mathrm{YBa}}_2{\mathrm{Cu}}_3{\mathrm{O}}_7$ and ${\mathrm{YBa}}_2{\mathrm{Cu}}_{3-y}{M}_y{\mathrm{O}}_7$ ($M=\mathrm{Ni},$ Zn). Deviations from these behaviors for both $R_H^{-1}$ and $\cot {\theta }_H$ are observed below a characteristic temperature $T^{*},$ whereby $T^{*}$ increases with decreasing $T_{c0\mathrm{}},$ i.e., increasing oxygen depletion. This implies a temperature-induced variation of the normal-state electronic spectrum and/or the scattering parameters governing the electronic transport of this material.