Link of Weak Ferromagnetism to Emergence of Topological Vortices in Bulk Ceramics of h-LuMn_xO₃ Manganite

Abstract

Research on topological defects in hexagonal manganites exposed uncovered properties of topologically protected domains and domain walls. Topological defects of h-REMnO 3 oxides (RE = Lu−Dy and Sc, In) modify essential multiferroic properties. Despite wide research with single crystals of stoichiometric composition, for the case of polycrystalline ceramics rare studies explored the effects of adjustment in chemical composition on phase transition temperatures, antiferromagnetic ordering, topological domain sizes, and potential modifications of the vortex density predicted by the Kibble− Zurek mechanism (KZM). The effect of cation vacancy doping of either Mn, or Lu sublattices of h-LuMn x O 3 , on appearance of ferroelectric vortices at the Curie point of apolar-to-polar ferroelectric ordering, T C , in bulk ceramics is investigated here. For cooling rates up to 40 K min −1 the Kibble−Zurek mechanism sets the density of FE vortices in ceramics of the LuMn x O 3 system. Magnetic hysteresis loops taken from the representative samples show sensitivity of remnant and magnetic coercivity field to FE vortex density. Magnetization measured from magnetic hysteresis loops supports theoretical predictions on induced net magnetization of the AFM walls and gives further evidence on the essential role of FE domain walls on multiferroic properties of h-REMnO 3 .

Interface Magnetism in Topological Armchair/Cove-Edged Graphene Nanoribbons

“…Topological phases, as a new phase of matter, have drawn intensive attention due to the ability to induce exotic states on the surfaces or edges of the material. , The states are extremely robust against defects and disorders because of the topology protection, giving rise to the outstanding characteristics. − Hence, topological materials are creating a range of new opportunities throughout electronics and have promising applications in variously relevant areas including quantum information and quantum computation. , Distinct topological phases have been identified in various materials. − Measurements have shown that three-dimensional (3D) topological materials exhibit spin-polarized 2D states on the surface, and 2D topological materials are quantum spin Hall insulators with novel 1D spin-polarized edge states. − Spin polarization is closely related to the topological phases and plays a critical role in determining properties of various topological materials. , …”