A new polar symmetry of huebnerite (MnWO4) with ferrodistortive domains

作者：Park S H^*; Mihailova B; Pedersen B; Paulmann C; Behal D; Gattermann U; Hochleitner R

来源：Journal of Magnetism and Magnetic Materials, 2015, 394: 160-172.

DOI：10.1016/j.jmmm.2015.06.039

• MnWO4
• Huebnerite
• Symmetry lowering
• Polarisation
• Ferrodistortive domains
• Multiferroic

Large-size single-crystal samples of huebnerite natural multiferroic MnWO4 were analyzed by neutron and synchrotron X-ray single-crystal diffraction as well as by polarized Raman spectroscopy. Both neutron and X-ray diffraction analyzes reveal polar space-group symmetry P2 for the nuclear structure of huebnerite via the detection of weak reflections hOl (l=odd) forbidden for the gliding plane c. Renninger scans of the reflection 301 on the neutron single-crystal cliffractometer RES1 (FRM-11) could confirm the absence of the gliding plane c in both para- and antiferromagnetic states of huebnerite. The symmetry breaking could be explained by structure analyzes with neutron single crystal diffraction data at 293 K revealing that two Mn atoms in P2 are displaced independently along the h axis from their equilibrium position at a polar point site, C-2 in P2/c, Micro X-ray diffraction and Raman-scattering mapping reveal a ferrodistortive domain texture in the room-temperature paramagnetic state of huebnerite, which is attributed to P2 domain formation through a proper similar to 180 degrees rotation about the reciprocal-space axis c*.

• 出版日期2015-11-15