Abstract
We report a magnetic state in GaV4Se8 which emerges exclusively in samples with mesoscale polar domains and not in polar mono-domain crystals. It is manifested by a sharp anomaly in the magnetic susceptibility and the magnetic torque, distinct from other anomalies observed also in polar mono-domain samples upon transitions between the cycloidal, the Néel-type skyrmion lattice and the ferromagnetic states. We ascribe this additional transition to the transformation of distinct magnetic textures, confined to polar domain walls (DW), to the ferromagnetic (FM) state. The emergence of these DW-confined magnetic states is likely driven by the mismatch of different spin spirals, hosted by the adjacent domains. A clear anomaly in the magneto-current indicates that the DW-confined magnetic states also have strong contributions to the magnetoelectric response. We expect polar DWs to commonly host such confined magnetic edge states and, thus, offer a fertile ground to explore novel forms of magnetism.
Highlights
Geometrical or dimensional constraints can promote the formation of new quantum phases which are absent in bulk systems.Prominent examples include metallic surface states in topological insulators[1], superconducting vortex state below the Kosterlitz–Thouless transition[2], interface-induced 2D electron gas[3] and superconductivity[4,5,6], integer and fractional quantum Hall edge states[7,8,9] and Wigner crystals[10,11] in systems with reduced dimensions
In attempt to observe spin cycloidal and Néel-type skyrmion textures within polar domains of GaV4Se8, only evidenced by small-angle neutron scattering measurements so far[43], we carried out magnetic force microscopy (MFM) measurements
A second purpose of the MFM study was to explore possible magnetic states confined to the vicinity of domain walls (DW), as reported in GaV4S818,42
Summary
Geometrical or dimensional constraints can promote the formation of new quantum phases which are absent in bulk systems.Prominent examples include metallic surface states in topological insulators[1], superconducting vortex state below the Kosterlitz–Thouless transition[2], interface-induced 2D electron gas[3] and superconductivity[4,5,6], integer and fractional quantum Hall edge states[7,8,9] and Wigner crystals[10,11] in systems with reduced dimensions. Geometrical or dimensional constraints can promote the formation of new quantum phases which are absent in bulk systems. Geometrical constraints on the nano- to mesoscale are usually enforced by design in quantum dots, nanowires, thin films, heterostructures, metamaterials, etc. Such constraints can be imposed naturally via mesoscale domain patterns or topological defects on the atomic scale[12,13,14,15,16,17,18,19]. Besides the peculiar electrical properties of DWs, the atomically sharp structural changes associated with them can substantially modify the magnetic exchange interactions and spin ordering, as reported for SrRuO3–Ca0.5Sr0.5TiO3 heterostructures and thin films of La2/3Sr1/3MnO3 and TbMnO319,25,26. Geometrical confinement were shown to substantially increase the thermal stability range of magnetic skyrmions[27,28,29], which are whirling spin textures on the nanoscale, and were proposed to generate exotic magnetic edge states, such as chiral bobbers[30]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
