Field-induced orientation of nonlevitated microcrystals of superconducting YBa2Cu3O7-x

X-ray diffraction patterns of superconducting YBa2Cu3O7-x particles which have typical dimensions D<5 m and do not levitate in an inhomogeneous magnetic field at T<Tc show marked evidence of particle alignment when powder specimens are subjected to a 0.5-T field at T<Tc, but reveal random orientation for T>Tc. A majority of the particles align preferentially with their antiphase twin boundary planes and a-b planes along the applied field, but a minority align with their b axes along the field. © 1988 The American Physical Society.