  The descloizite-type compound, SrMn(VO4)(OH), was synthesized as large single
crystals using a high-temperature high-pressure hydrothermal technique. X-ray
single crystal structure analysis reveals that the material crystallizes in the
acentric orthorhombic space group of P212121. The structure exhibits a
one-dimensional feature, with MnO4 chains propagating along the a-axis which
are interconnected by VO4 tetrahedra. Raman and infrared spectra were obtained
to identify the fundamental vanadate and hydroxide vibrational modes.
Magnetization data reveal a broad maximum at approximately 80 K, arising from
one-dimensional magnetic correlations with intrachain exchange constant of J/kB
= 9.97(3) K between nearest Mn neighbors and a canted antiferromagnetic
behavior below TN = 30 K. Single crystal neutron diffraction at 4 K yielded a
magnetic structure solution in the lower symmetry of the magnetic space group
P21 with two unique chains displaying antiferromagnetically ordered Mn moments
oriented nearly perpendicular to the chain axis. The presence of the
Dzyaloshinskii Moriya antisymmetric exchange interaction leads to a slight
canting of the spins and gives rise to a weak ferromagnetic component along the
chain direction.
