ANISOTROPY OF AC MAGNETIC-SUSCEPTIBILITY AND J(C) IN YBCO BULK TEXTURED SAMPLES AND SINGLE-CRYSTALS

a.c. magnetic susceptibility chi of single crystals and two types of b ulk textured slabs, differing by in c-axis orientation, have been stud ied. The measurements are carried out in the condition of the simple r elation between chi and J(c). The results obtained do not depend on th e geometrical sample factors but are defined by the d.c. magnetic fiel d H > H-p orientation in relation to the crystallographic axis. We obs erve a qualitative difference of the angular dependence of the critica l current density J(c) for the textured samples and single crystals. T he results are discussed and connected with structural features of the se materials.