화학공학소재연구정보센터
Molecular Crystals and Liquid Crystals, Vol.475, 221-231, 2007
Inverse frederiks effect and bistability in ferronematic cells
In recent work we have examined switching properties of a ferronematic in an external magnetic field in a cell with homeotropic boundary conditions, and subject also to a bias field in the plane of the cell. There are three regimes, depending on the strength of the director-ferroparticle coupling. For low coupling, there is a high field inverse Frederiks transition to an undistorted phase. At low non-dimensional temperatures, high magnetic fields can cause the ferroparticles to segregate. Segregation-director distortion coupling can drive the inverse Frederiks transition first order, causing bistability. This article considers homogeneous planar, rather than homeotropic anchoring at the cell walls and particle surfaces. The bias field is unnecessary, but the basic physical picture is retained, with the same set of regimes. The lack of bias field means that this case is a more suitable model for basic studies.