Writing of strain-controlled multiferroic ribbons into MnWO4

Abstract

Local and low-dimensional structures, such as interfaces, domain walls and structural defects, may exhibit physical properties different from the bulk. Therein, a wide variety of local phases were discovered including conductive interfaces, sheet superconductivity, and magnetoelectric domain walls. The confinement of combined magnetic and electric orders to spatially selected regions may be particularly relevant for future technological applications because it may serve as basis of electrically controllable magnetic memory devices. However, direct observation of magnetoelectric low-dimensional structures cannot readily be done partly because of the lack of experimental techniques locally probing their physical nature. Here, we report an observation of multiferroic ribbon-like domains in a non-multiferroic environment in MnWO4. Using optical second harmonic generation imaging, we reveal that a multiferroic phase is stabilized by locally generated strain while the bulk magnetic structure is non-multiferroic. We further find that the confined multiferroic state retains domains with different directions of electric polarization and we demonstrate deterministic writing of a multiferroic state embedded in a non-multiferroic environment.

Two-dimensional multiferroic material of metallic p-doped SnSe

“…However, the ferroelectricity often derives from the residual polarization due to the stable off-centered ion with empty d/f orbitals, which breaks the space-inversion symmetry 11 . In this regard, the exploration of multiferroic in low symmetry materials is promising and considerable efforts have also been made (e.g., NiI 2 1 , GaFeO 3 12 , BiFeO 3 13 , TbMnO 3 14 , and MnWO 4 15 , etc). Although two-dimensional (2D) multiferroic materials have long been sought for constructing high-performance magnetoelectric coupling devices, the progress is still unsatisfactory.…”

Two-dimensional multiferroic material of metallic p-doped SnSe

“…However, the ferroelectricity often derives from the residual polarization due to the stable off-centered ion with empty d/f orbitals, which breaks the space-inversion symmetry 11 . In this regard, the exploration of multiferroism in low symmetry materials is promising and considerable efforts have also been made (e.g., NiI 2 1 , GaFeO 3 12 , BiFeO 3 13 , TbMnO 3 14 , and MnWO 4 15 , etc).…”

Anisotropic Strain-Tailoring Nonlinear Optical Response in van der Waals NbOI2

“…The stronger SHG response at lower temperatures is probably due to the more stabilized polarizations arising from the quenched thermal vibration and expansion of the lattice (Figure S6b,d). , …”

“…40 The stronger SHG response at lower temperatures is probably due to the more stabilized polarizations arising from the quenched thermal vibration and expansion of the lattice (Figure S6b,d). 41,42 To investigate the anisotropy of the SHG response in NbOI 2 crystals under directional strain profiles, we apply uniaxialstrain along both b-axis and c-axis by mechanically bending a flexible substrate (polyethylene terephthalate, PET) with NbOI 2 flakes on top using a micromanipulator (left panel of Figure 3a). The applied strain is estimated by using the equation ε = τ/(2R) based on the curving geometry, 43 where τ is the thickness of the substrate (0.188 mm) and R is the radius of curvature, as shown in the right panel of Figure 3a.…”