Helical Spin Dynamics in Commensurate Magnets: a Study on Brochantite, Cu${}_4$SO${}_4$(OH)${}_6$

S. E. Nikitin, Tao Xie, A. Gazizulina +8

We report the direct observation of a commensurate-ordered antiferromagnetic (AFM) state but incommensurate helical spin dynamics in the natural mineral brochantite Cu${}_4$SO${}_4$(OH…