Texture development due to preferential grain growth of Ho–Ba–Cu–O in 1.6-T magnetic field

Abstract

It has been experimentally observed that the application of even a relatively weak magnetic field of 1.6 T during sintering of HoBa2Cu3O7-δ (hereafter HoBCO) results in a significant degree of grain alignment. The orientation of grains is found to be controlled by the direction and magnitude of a magnetic field. The degree of alignment was monitored by x-ray diffraction measurements on the flat surface of the samples and by metallography. It has been observed that the degree of alignment grows as the magnitude of the field increases between 0 and 1.6 T for a fixed temperature and processing time. The degree of alignment also increases when the processing temperature changes from 930 °C to 965 °C for a fixed field and time. It has also been observed that for both a fixed field and processing temperature, the alignment grows when the processing time increases between 16 and 72 h. Metallography measurements on the flat and cross-sectional parts of the samples showed that the texture propagates into the bulk of the samples. In the presence of a sufficient amount of the liquid phase, the enhancement of the grain growth in the direction favorable to the magnetic field produces rather large single crystals (0.3 to 0.5 mm linear size) within the sample.