The twin-planes (TP) effect on pinning is studied in large monodomain ${\mathrm{YBa}}_2{\mathrm{Cu}}_3{\mathrm{O}}_7$ textured samples with the size along the c axis greater than the others. The magnetic field angular dependence of the c-axis resistivity and c-axis critical current density has been carried out using transport and dc-magnetization measurements. These various experimental methods show clearly that in this configuration TP’s dominate the pinning properties in the ab planes at high temperatures $(T>~40\mathrm{K})$ and when the magnetic field is close to the TP directions. Moreover, experiments demonstrate that the TP’s enhance the ab-plane irreversibility line for angles close to a critical angle ${\Phi }_c\sim 8°–10°.$ The observed properties are related to the extended and correlated character of the twin planes. An experimental phase diagram for the angular dependence of the ab-plane irreversibility line is proposed with a possible existence of a Bose glass phase in the ab plane induced by the two directions of the TP’s. The persistence of the TP pinning for magnetic fields higher than 20 T is explained with an electromagnetic origin induced by the surface character of TP’s.

• Received 9 March 1998

DOI:https://doi.org/10.1103/PhysRevB.58.15189