We present magneto-optic measurements on two materials that form the recently discovered twist-bend nematic ($N_{\mathrm{tb}}$) phase. This intriguing state of matter represents a fluid phase that is orientationally anisotropic in three directions and also exhibits translational order with periodicity several times larger than the molecular size. $N_{\mathrm{tb}}$ 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 25$T$ external magnetic field depresses the $N$-$N_{\mathrm{tb}}$ phase transition temperature by almost 1${}^{\circ }$C. We propose a quantitative mechanism to account for this shift and suggest a Helfrich-Hurault-type mechanism for the optical stripe formation.

• Received 17 December 2013

DOI:https://doi.org/10.1103/PhysRevE.89.060501