At about $P=17\mathrm{}$ kbar Eu${\mathrm{As}}_3$ undergoes a pressure-induced phase transition from a commensurate phase with magnetic moments parallel to ± [010] to an incommensurate spiral phase with magnetic moments modulated in the (010) plane. At $P=4\mathrm{}$ kbar, the ambient pressure commensurate and incommensurate phases are still stable. However, the soliton-lattice behavior of temperature variation of the modulation vector of the incommensurate phase at $P=1\mathrm{}$ bar crosses over to a linear behavior at $P=4\mathrm{}$ kbar.

• Received 27 April 1987

DOI:https://doi.org/10.1103/PhysRevB.36.2454