Composition, structure, and electrical properties of Bi2Sr2Ca1−yYyCu2O8: A single-crystal study

Abstract

A systematic study of yttrium substitution for calcium in the high-temperature superconductor ${\mathrm{Bi}}_2$ ${\mathrm{Sr}}_2$ ${\mathrm{CaCu}}_2$ ${\mathrm{O}}_8$ has been performed. Single crystals were grown, cleaved, and characterized with use of x-ray fluorescence, electron microprobe, and electron- and x-ray-diffraction techniques. The dc resistivity, diamagnetic shielding, and Hall coefficient of the samples were also measured as functions of the temperature from 4 to 300 K for different dopant concentrations. We conclude that our systematic substitution in the family ${\mathrm{Bi}}_2$ ${\mathrm{Sr}}_2$ ${\mathrm{Ca}}_{1\mathrm{-}\mathit{y}}$ ${\mathrm{Y}}_{\mathit{y}}$ ${\mathrm{Cu}}_2$ ${\mathrm{O}}_8$ gives an insight into this high-temperature superconducting material as well as into weak localization and metal-insulator transitions.