Defect Control in Nematic Shells through Magnetic Fields

Abstract

We are studying to control the defect number of the nematic shell by applying a magnetic field. In this work, we focused on the effect of shell thickness and diameter on the defect of the nematic under a constant magnetic field. Three types of reorientation processes were observed; (1) In the thin shells, defects did not merge but director aligned along magnetic direction and bipolar configuration was formed. (2) In the slightly thicker shells, two of +1/2 defects merged in one of +1 defect at the pole of the bipolar configuration. (3) In the thick shell, defects nucleated at the pole of the shells and replaced the initial defects. We focus on defect marge phenomena, and observed the reorientation under the magnetic field at various temperatures. As a result we found critical angle between two of +1/2 defects before marge.