A compound with large anions is known to show large compressibility, whereby a novel response may emerge from the degenerated state by a uniaxial pressure. Neutron scattering study of BaCo0.9Ni0.1S1.9 crystal reveals that the tetragonal insulating state has two magnetic domains with in-plane anisotropic antiferromagnetic wave vectors Q1=(π,0) and Q2=(0,π). The magnetic order with in-plane broken C4 symmetry is realized as a twin of these two domains in the tetragonal state without any strain. One magnetic domain with Q2 becomes dominant under a weak strain without any appreciable structural distortion. Correspondingly, the in-plane broken C4 symmetry is also observed in the in-plane magnetic excitation of the tetragonal state.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)