Growth, characterization and physical properties of high-quality large single crystals ofBi2(Sr2−xLax)CuO6+δ high-temperature superconductors

Abstract

High-quality large Bi2(Sr2−xLax)CuO6+δ (La–Bi2201) single crystals have been successfully grown by the traveling solventfloating zone technique. The samples are characterized by compositional andstructural analyses and their physical properties are investigated by magneticsusceptibility and resistivity measurements. Superconducting samples with sharpsuperconducting transitions are obtained, covering a wide range of doping from overdoped(x<0.40), optimallydoped (x∼0.40),underdoped (0.40<x<0.84) to heavily underdoped without superconducting transition(x>0.84). Crystals aslarge as ∼40 × 2.0 × 1 mm3 areobtained for x = 0.73. A sharp superconducting transition with a width less than 2 K anda nearly perfect Meissner signal of superconductivity are achieved forx = 0.40. The availability of the La–Bi2201 single crystals will provide an ideal system to studythe physical properties, electronic structure and mechanism of high-temperaturesuperconductivity.