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Abstract Ferroelectric topological objects provide a fertile ground for exploring emerging physical properties that could potentially be utilized in future nanoelectronic devices. Here, we demonstrate quasi-one-dimensional metallic high conduction channels associated with the topological cores of quadrant vortex domain and center domain (monopole-like) states confined in high quality BiFeO 3 nanoislands, abbreviated as the vortex core and the center core. We unveil via the phase-field simulation that the superfine metallic conduction channels along the center cores arise from the screening charge carriers confined at the core region, whereas the high conductance of vortex cores results from a field-induced twisted state. These conducting channels can be reversibly created and deleted by manipulating the two topological states via electric field, leading to an apparent electroresistance effect with an on/off ratio higher than 10 3 . These results open up the possibility of utilizing these functional one-dimensional topological objects in high-density nanoelectronic devices, e.g. nonvolatile memory. 

The biological effect of ultrasound on bone regeneration has been well documented, yet the underlying mechanotransduction mechanism is largely unknown. In relation to the mechanobiological modulation of the cytoskeleton and Ca²⁺influx by short‐term focused acoustic radiation force (FARF), the current study aimed to visualize and quantify Ca²⁺oscillations in real‐time ofin situandin vivoosteocytes in response to focused low‐intensity pulsed ultrasound (FLIPUS). Forin situstudies, fresh mice calvaria were subjected to FLIPUS stimulation at 0.05, 0.2, 0.3, and 0.7 W. For thein vivostudy, 3‐month‐old C57BL/6J Ai38/Dmp1‐Cre mice were subjected to FLIPUS at 0.15, 1, and 1.5 W. As observed via real‐time confocal imaging,in situFLIPUS led to more than 80% of cells exhibiting Ca²⁺oscillations at 0.3–0.7 W and led to a higher number of Ca²⁺spikes with larger values at >0.3 W.In vivoFLIPUS at 1–1.5 W led to more than 90% of cells exhibiting Ca²⁺oscillations. Higher FLIPUS energies led to larger Ca²⁺spike magnitudes. In conclusion, this study provided a pilot study of bothin situandin vivoosteocytic Ca²⁺oscillations under noninvasive FARF, which aids further exploration of the mechanosensing mechanism of the controlled bone cell motility response to the stimulus.

 

A strain‐driven BiFeO₃(BFO) tetragonal to rhombohedral phase transition is demonstrated in self‐assembled BiFeO₃‐CoFe₂O₄(BFO‐CFO) nanocomposites on LaAlO₃(110)‐oriented substrates with varying thickness. The CFO forms parallel nanoscale fin‐shaped structures within a BFO matrix. Out‐of‐plane lattice strain from the BFO/CFO interfaces stabilizes the BFO rhombohedral‐like phase. The BFO exhibits a range of ferroelectric textures including stripe domains and centered domain arrangements, and the magnetic anisotropy of CFO shows a thickness‐dependent reorientation.