Uniaxial anisotropic flux trapping in Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O single crystals

Measurements of the angular dependence of the remanent magnetization of Y-Ba-Cu-O and of Bi-Sr-Ca-Cu-O single crystals reveal uniaxial anisotropy for flux trapping; the anisotropy axis is the crystalline c axis. The amount of trapped flux is determined by the component of the field H along c. For flux trapping with H in the a-b plane, we observe unidirectional anisotropy; the anisotropy direction is defined by H during the cooling process.