Electrical resistivity and magnetization studies of the high-temperature superconductor Tl2Ca2Ba2Cu3O10

Abstract The magnetization of polycrystalline samples of Tl 2 Ca 2 Ba 2 Cu 3 O 10 showing zero resistivity at temperatures as high as 120.5 K have been studied in the temperature range 4–300 K and in magnetic fields up to 60 kOe. In fields below 50 Oe the diamagnetic properties are dominated by supercurrents flowing across weak-link grain boundaries in the sintered material. H cl (4.2 K) takes on the value ∼900 Oe. The samples are dense and homogeneous enough to remain nearly perfectly diamagnetic to temperatures up to ∼100 K. From the high-field magnetic hysteresis loop we estimate the intragrain critical supercurrent density to be ∼7 × 10 6 A/cm 2 at 4 K. The magnetic susceptibility in the normal state can be analyzed in terms of a sizeable Curie-Weiss term plus a constant; the constant takes on an almost identical value per mol Cu to that found previously for superconducting La 1.85 Sr 0.15 CuO 4 and YBa 2 Cu 3 O 7 .