Different types of subtle lattice anomalies (Δl/l∼10 -5) are reported in the multiferroic Mn 1-xCo xWO 4 (x = 0.05 and 0.20) compounds coinciding with the successive magnetic transitions below 30 K. Clearly different magnetoelastic effects at the ferroelectric transition (T FE=T N2) were observed for Mn 0.95Co 0.05WO 4 (single-k pure cycloidal order below T FE) and Mn 0.80Co 0.20WO 4 (double-k conical order below T FE). The different lattice evolution across T FE results from a distinct relative orientation of the magnetic easy axis and the spiral plane. Whereas both are parallel in Mn 0.95Co 0.05WO 4, the spiral plane is perpendicular to the easy axis in Mn 0.80Co 0.20WO 4. © 2012 American Physical Society.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 9 Nov 2012|