TEXTURE AND MAGNETIC LEVITATION FORCE OF MELT-TEXTURED YBaCuO CYLINDERS

To investigate the correlation between the levitation force of YBaCuO cylinders when approached by a permanent magnet and the texture of these YBaCuO cylinders some of these specimens were selected which are free of microcracks, have the same oxygen load, show no isotropic fraction or other undesired parasitic c-axis orientations. To gain a maximum levitation force the c-axis orientation of the crystalline domains has to have a small divergence between the c-axis and the cylinder axis. By measurements of the (002) pole figures by neutron diffraction with a mesh width no more than 6° undesired c-axis orientations have been analyzed. The distribution of the c-axis near the cylinder axis has been measured at the (005) reflection of 7 times higher intensity than the (002) reflection. The angular limit within which lie 94% of all c-axis orientations is a practical value for comparison of the c-axis orientations and the levitation forces of the different YBaCuO cylinders.