Thermally Enhanced Pseudo-Goldstone Spin Gap in the Isotropic Helimagnet ZnCr${}_2$Se${}_4$

N. D. Andriushin, A. Sanders, J. Reuther +8

In magnetically ordered systems, the spin gap in the magnon spectrum is normally expected to decrease on warming and close at the transition out of the long-range order. The presen…