Abstract
single crystals are prepared by a KCl flux method. Transport properties and crystal structures are investigated for the samples with various ’s. The result of structural analysis indicates that the change of ’s caused by the overdoping of the hole carrier through excess oxygen located between double Tl-O sheets. The out-of-plane resistivity is larger than for , but smaller than for . Temperature dependences of are metallic for both overdoped nonsuperconducting and 75-K superconducting samples. The temperature dependence of in-plane resistivity changes from ∼ to ∼ with increasing . The Hall coefficient exhibits a characteristic maximum at about 100 K for all samples. However, inverse Hall mobility (=ρ/) always shows clear dependence regardless of the values, which suggests that the scattering rate of this material has ∼ dependence, just as in an ordinary Fermi liquid, and that the carrier concentration actually changes like that observed in (=1/e).
- Received 27 April 1992
DOI:https://doi.org/10.1103/PhysRevB.46.11019
©1992 American Physical Society