Manipulation of magnetic nanowire suspending in half space nematic liquid crystal by external magnetic field

摘要

Based on the elasticity energy, a magnetic nanowire suspended in a half-space twisted nematic liquid crystal (TNLC) was studied. Using equivalent capacitance, the equilibrium position of the nanowire, the deflexion of its axis from the anchoring direction and the eigenfrequency of the nanowire around its equilibrium position were calculated. The results show that the height of the nanowire increases slowly with increasing H in small magnetic field regime less than 0.01 Gs, and picks up quickly if H is larger than about 0.02 Gs. A calculation of the eigenfrequency of the nanowire shows that it decreases quickly with the increase of H at small magnetic field regime and then levels off towards a lower limit, which is about 170 Hz based on the present parameters under larger field. Moreover, the eigenfrequency also depends on mass with a maximum value which is found to be field-independent when the external field is large enough.