Angle dependence of magnetization in a single-domain YBa2Cu3Ox sphere

The crystal angle dependence of magnetization has been measured in spherically shaped, single-domain YBa2Cu3Ox ~YBCO!. The single-domain sample is processed by a seeded-melt growth process in which a small NdBa2Cu3Ox seed is used to induce domain growth through a peritectic reaction in YBCO. It has been found that the angle dependence of magnetization can be obtained in a series of zero-field-cooled hysteresis loop measurements with warm-ups well above Tc between each measurement at a specific angle. In contrast to previously reported results, we have found that the angle dependence exhibits a sawtooth wave between 0° and 360° over a wide range of temperatures and fields. Furthermore, we have also measured the angle dependence on a YBCO plate and found similar behavior, indicating that the sawtooth wave is intrinsic to the superconductor. A physical model has been developed to explain the angle dependence of magnetization observed in this experiment. @S0163-1829~98!05541-6#