Synthesis and physical properties of Tl 2Ba 2CuO 6+δ single crystal

Abstract

Tl 2 Ba 2 CuO 6+δ single crystals were prepared using a KCl flux method. Obtained crystals were thin plates grown in the a–b plane with a typical size of 2 × 2 × 0.01 mm 3 . The T c value was controlled from 0 K (nonsuperconducting normal metal) to 75 K by annealing in oxygen or argon atmosphere. The temperature dependence of the in-plane resistivity, ρ ab , changed from T 2 to T 1 with increasing T c . The in-plane Hall coefficient R H was about +1 × 10 −3 cm 3 /C and exhibited a broad maximum at about 100 K. These results are very similar to those for ceramic samples. The resistivity along the c -axis, ρ c , showed metallic temperature dependence for all T c 's. The ratio of anisotropic resistivity (ρ c /ρ ab ) measured by the Montgomery method was as large as 6 × 10 2 at room temperature even for a normal metallic sample.