Magnetic Tri-Axial Grain Alignment Achieved in Bismuth-Based Cuprate Superconductors

Abstract

We demonstrate the tri-axial magnetic alignment of Bi2Sr2CaCu2Oy [Bi2212] and Bi1.7Pb0.35Sr2Ca2Cu3Oy [(Bi1.7Pb0.35)2223] and report the semi-quantitative tri-axial magnetic anisotropy of Bi2212. A modulated rotating magnetic field of 10 tesla achieved degrees of in-plane and c-axis orientations of <9 and ∼4°, respectively. Conversion of magnetization axes of Bi2212 by slight Er-doping suggests that the incommensurate modulated crystal structures observed in the Bi-based cuprates induced generation of weak but strictly tri-axial magnetic anisotropy. Our present results indicate the possibility of fabricating tri-axially grain-oriented bulks and thick films without applying epitaxial growth methods, such as melt solidification and thin-film deposition.