Twist-bend nematic liquid crystals in high magnetic fields

We present magneto-optic measurements on two materials that form the recently discovered twist-bend nematic (Ntb) phase. This intriguing state of matter represents a new fluid phase that is orientationally anisotropic in three directions and also exhibits translational order with periodicity several times larger than the molecular size. NTB materials may also spontaneously form a visible, macroscopic stripe texture. We show that the optical stripe texture can be persistently inhibited by a magnetic field, and a 25T external magnetic field depresses the N-Ntb phase transition temperature by almost 1 degree C. We propose a quantitative mechanism to account for this shift and suggest a Helfrich-Hurault-type mechanism for the optical stripe formation.