Magnetic phase transitions ofMnWO4studied by the use of neutron diffraction

Neutron diffraction, magnetic, and magnetoelectric studies of phase transitions in multiferroic Mn0.90Co0.10WOUrcelay-Olabarría1, Ressouche2, Mukhin3 et al. 2012Phys. Rev. B237390View full textAdd to dashboardCite

“…The crystal structure is similar to that of pure MnWO 4 compound: 9 it consists of alternating layers of manganese/cobalt and tungsten atoms parallel to the (1 0 0) plane. The oxygen anions form distorted octahedra that are aligned in zig-zag chains along the c axis and the manganese ions are located in the center of the octahedra.…”

“…[9][10][11] It crystallizes in the wolframite structure (monoclinic space group P 2/c). 9,10 When decreasing temperature, it undergoes three successive phase transitions to different long-range antiferromagnetic states.…”

“…[9][10][11] It crystallizes in the wolframite structure (monoclinic space group P 2/c). 9,10 When decreasing temperature, it undergoes three successive phase transitions to different long-range antiferromagnetic states. Below T N = 13.5 K moments order collinearly along a directionû within the ac plane, with a sinusoidal modulation of the amplitudes (so-called AF3 magnetic phase), with k = (−0.214 1 2 0.457).…”

Effect of Nonmagnetic Substituents Mg and Zn on the Phase Competition in the Multiferroic Antiferromagnet MnWO4

“…[4][5][6][7][8][9][10][11] MnWO 4 undergoes three magnetic phase transitions in zero magnetic field below 14 K (Figure 1). 12 With decreasing temperature, MnWO 4 first transforms from a paramagnetic (PM) state to a collinear spin sinusoidal state (AF3) at T N ≈ 13.5 K, then to a tilted elliptical spiral spin state (AF2) at T 2 ≈ 12.3 K, and eventually to a up-up-down-down collinear spin structure (AF1) at T 1 ≈ 8.0 K. The magnetic structures of the AF3 and AF2 states are ICM to the lattice spacing with propagation vector k = (-0.214, 0.5, 0.457), while that of the AF1 state is commensurate (CM) with propagation vector k = (-0.25, 0.5, 0.5). 12 The loss of inversion symmetry due to the helical spin ordering at T 2 makes MnWO 4 exhibit ferroelectric polarization in the AF2 state, and T 2 is also the ferroelectric critical temperature.…”

Thermal expansion and pressure effect in

“…Below 15 K competing magnetic exchange interactions result in a high level of magnetic frustration with several magnetically ordered states quasi-degenerated in energy. As a consequence, M nW O 4 undergoes three successive magnetic transitions, antiferromagnetic (AFM) order of the Mn-spins with an IC sinusoidal spin modulation appears at T N =13.5 K (AF3 phase) followed by an elliptical IC magnetic order below T 2 =12.6 K (AF2 phase) and a commensurate collinear magnetic phase below T 1 =7.8K (AF1 phase) [4]. Ferroelectricity was observed in the AF2 phase only and it can qualitatively be explained by the loss of inversion symmetry due to the helical magnetic order and a strong spin-lattice coupling [5].…”