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Bismuth ferrite (BiFeO 3 ) nanocomposites were synthesized using a novel nano-agitator bead milling method followed by calcination. Bismuth oxide and iron oxide nanoparticles were mixed in a stoichiometric ratio and milled for 3 h and calcined at 650 °C in air. X-ray diffraction with Rietveld refinement, scanning electron microscopy, and transmission electron microscopy techniques were used to elucidate the structure of BiFeO 3 . The particle diameter was found to be ∼17 nm. Magnetic and electrical measurements were performed, and these results were compared with those of similar methods. Mostly, BiFeO 3 was obtained with minor secondary phase formation. The resulting powder was weakly ferromagnetic with a remnant magnetization of 0.078 emu/g. This can be attributed to residual strain and defects introduced during the milling process. Electrical testing revealed a high leakage current density that is typical of undoped bismuth ferrite. 

The van der Waals magnets CrX₃(X = I, Br, and Cl) exhibit highly tunable magnetic properties and are promising candidates for developing novel two‐dimensional (2D) spintronic devices such as magnetic tunnel junctions and spin tunneling transistors. Previous studies of the antiferromagnetic CrCl₃have mainly focused on mechanically exfoliated samples. Controlled synthesis of high quality atomically thin flakes is critical for their technological implementation but has not been achieved to date. This work reports the growth of large CrCl₃flakes down to monolayer thickness via the physical vapor transport technique. Both isolated flakes with well‐defined facets and long stripe samples with the trilayer portion exceeding 60 µm have been obtained. High‐resolution transmission electron microscopy studies show that the CrCl₃flakes are single crystalline in the monoclinic structure, consistent with the Raman results. The room temperature stability of the CrCl₃flakes decreases with decreasing thickness. The tunneling magnetoresistance of graphite/CrCl₃/graphite tunnel junctions confirms that few‐layer CrCl₃possesses in‐plane magnetic anisotropy and Néel temperature of 17 K. This study paves the path for developing CrCl₃‐based scalable 2D spintronic applications.

 

Magnetron sputtering inert gas condensation is used to produce core/shell Co/ZnO nanoparticles. Selective oxidation to form the core/shell nanoparticles is accomplished both during nanoparticle formation (“in situ”) and with exposure to ambient conditions (“ex situ”). The ZnO formed in situ shows single‐crystalline nature with specific orientation relationships with the Co core, while the ZnO formed ex situ is polycrystalline. Conductive atomic force microscopy is utilized to measure the electrical behavior of individual nanoparticles, and both types of core/shell nanoparticles display classic bipolar resistive switching behavior. These results highlight potential application of these nanoparticles as promising next generation nonvolatile memories and neuromorphic computational devices.

 

The flexible, transparent, and low‐weight nature of ferroelectric polymers makes them promising for wearable electronic and optical applications. To reach the full potential of the polarization‐enabled device functionalities, large‐scale fabrication of polymer thin films with well‐controlled polar directions is called for, which remains a central challenge. The widely exploited Langmuir–Blodgett, spin‐coating, and electrospinning methods only yield polymorphous or polycrystalline films, where the net polarization is compromised. Here, an easily scalable approach is reported to achieve poly(vinylidene fluoride‐trifluoroethylene) P(VDF‐TrFE) thin films composed of close‐packed crystalline nanowires via interface‐epitaxy with 1T′‐ReS₂. Upon controlled thermal treatment, uniform P(VDF‐TrFE) films restructure into about 10 and 35 nm‐wide (010)‐oriented nanowires that are crystallographically aligned with the underlying ReS₂, as revealed by high‐resolution transmission electron microscopy. Piezoresponse force microscopy studies confirm the out‐of‐plane polar axis of the nanowire films and reveal coercive voltages as low as 0.1 V. Reversing the polarization can induce a conductance switching ratio of >10⁸in bilayer ReS₂, over six orders of magnitude higher than that achieved by an untreated polymer gate. This study points to a cost‐effective route to large‐scale processing of high‐performance ferroelectric polymer thin films for flexible energy‐efficient nanoelectronics.

 

Domain wall nanoelectronics is a rapidly evolving field, which explores the diverse electronic properties of the ferroelectric domain walls for application in low‐dimensional electronic systems. One of the most prominent features of the ferroelectric domain walls is their electrical conductivity. Here, using a combination of scanning probe and scanning transmission electron microscopy, the mechanism of the tunable conducting behavior of the domain walls in the sub‐micrometer thick films of the technologically important ferroelectric LiNbO₃is explored. It is found that the electric bias generates stable domains with strongly inclined domain boundaries with the inclination angle reaching 20° with respect to the polar axis. The head‐to‐head domain boundaries exhibit high conductance, which can be modulated by application of the sub‐coercive voltage. Electron microscopy visualization of the electrically written domains and piezoresponse force microscopy imaging of the very same domains reveals that the gradual and reversible transition between the conducting and insulating states of the domain walls results from the electrically induced wall bending near the sample surface. The observed modulation of the wall conductance is corroborated by the phase‐field modeling. The results open a possibility for exploiting the conducting domain walls as the electrically controllable functional elements in the multilevel logic nanoelectronics devices.