Texture induced by uniaxial pressure in the YBa_{2Cu_{30_{7-y compound

After uniaxial powder pressing under sufficient pressure, the green compacts of the YBa2Cu307–y (YBCO) compound revealed strong degree of texture with the c–axis preferentially parallel to the press axis. After sintering in air at 950°C for 3 hr, freshly ground powder compacts still remain high degree of preferred orientation, while the pellets compacted from the milled and dried powders almost lost their texturing. There are two kinds of mechanism to induce texture by uniaxial powder pressing. One is the mechanical deformation, and the other is related to the pressureinduced grain alignment in the powder state. The latter may be one kind of the uniaxial piezoelectric effect