Control of the polarization flop direction by a tilted magnetic field in multiferroicTbMnO3

Correlation between magnetocapacitance effect and polarization flop direction in a slanted magnetic field in multiferroic helimagnets

“…The crystal axes were determined by Laue photograph. To measure the rotation direction of P, the crystals were cut into plate-shaped samples with the normal vector forming an angle of 45 • from both the a-and the c-axes [13]. Gold films were deposited onto the widest surfaces to form the counter electrodes.…”

“…2 (a) and (b), the sample was cooled from 45 K to below the P||c phase transition temperature in a positive electric field to form a single-domain state with P c > 0. The direction of the canted magnetic field is represented by two angles, ω and θ [13]. Then, the a-and c-components of the magnetic field are given by H a = H sin θ and H c = H cos θ sin ω, respectively.…”

“…In the case of the prototypical ferroelectric helimagnet RMnO 3 (R = Tb, Dy), P rotates from along the c-axis to along the a-axis when a magnetic field is applied along the b-axis [1,12]. Moreover, if the magnetic field is slightly canted from the b-axis, then the rotation direction of P can be controlled by the tilting direction of the magnetic field [13]. Because the phase transition is of first-order type, P||c and P||a phases can coexist near the phase transition, and hence four types of 90 • DWs appear as their boundaries: +P c to +P a , +P c to −P a , −P c to +P a , and −P c to −P a .…”

Room-temperature ferromagnetism and ferroelectricity of nanocrystalline La2Ti2O7

“…Generally, most ferromagnetic oxides contain the center of symmetry and do not show electric polarization, while most sintered ferroelectric bulks are not magnetic [2]. However, more and more multiferroic materials were reported in recent years [3][4][5][6][7][8][9][10][11][12][13], e.g. TbMnO 3 [3,7], BiFeO 3 [5] and BiMnO 3 [6].…”

“…However, more and more multiferroic materials were reported in recent years [3][4][5][6][7][8][9][10][11][12][13], e.g. TbMnO 3 [3,7], BiFeO 3 [5] and BiMnO 3 [6]. It can be expected that for the multiferroics with ferromagnetic and ferroelectric ordering simultaneously, the coupling between the magnetic and electric properties will lead to the magnetoelectric (ME) effect [1,3,[5][6][7]9] in which the magnetization can be controlled by application of electric fields, and vice versa.…”