The resistivity ρ and Hall coefficient ${\mathit{R}}_{\mathit{H}}$ have been measured for samples of the two-plane superconductor ${\mathrm{HgBa}}_2$${\mathrm{CaCu}}_2$${\mathrm{O}}_{6+\mathrm{\delta }}$ (${\mathit{T}}_{\mathit{c}}$∼124 K) with different annealing histories. The observed temperature dependence ${\mathit{R}}_{\mathit{H}}$∼1/T (up to 470 K) matches the steep dependence previously seen in 90-K ${\mathrm{YBa}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{7\mathrm{-}\mathrm{\delta }}$ and indicates low-impurity scattering. We find T-linear behavior for ρ in the lowest-resistivity samples and confirm that cot${\mathrm{\theta }}_{\mathit{H}}$∼${\mathit{T}}^2$. These findings add support to Anderson’s proposal of distinct longitudinal and transverse scattering times.

• Received 5 April 1994

DOI:https://doi.org/10.1103/PhysRevB.50.3246