Magnetorotation experiment of diamagnetic single-crystal grains suspended in a gas medium for examining dust alignment in the interstellar region

The magnetic alignment of diamagnetic grains suspended in a gas medium is o bserved for the first time on micron-sized single crystals of graphite by t he use of a system newly developed for this purpose. Previously magnetic al ignment was studied on grains suspended in a liquid medium. The field of fu ll orientation H-s at T = 293 K was as small as 140 G when the crystal size was 3.5 mum in diameter and 1.0 mum in thickness. It was examined experime ntally that the alignment in the gas medium depends on the balance between the thermal agitation energy and the diamagnetic anisotropy energy induced in the particle. This experiment is necessary ill order to examine the grai n alignment of the interstellar region. which is the basis to observe the i nterstellar magnetic field. The experiment is necessary also to determine t he diamagnetic anisotropy for various inorganic materials through high-temp erature measurements.