Observation of alignment of superconducting ${\mathrm{YBa}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_7$ particles in a magnetic field using neutron diffraction

Neutron-diffraction measurements have been performed on powdered, sintered-pellet, and pressed-powder samples of ${\mathrm{YBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_7$ in the superconducting mixed state. In the powdered sample, the presence of the vertical applied magnetic field is found to cause an irreversible increase in the intensity of the (001) Bragg peak measured in the horizontal plane. This effect is consistent with orientation of the particles in the field. No changes due to the field are observed in the sintered pellet or the pressed powder.