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Abstract The high thermal gradient and solidification velocity associated with the laser powder bed fusion process spurs formation of diverse microstructures in additively manufactured materials. This study focused on the phase composition observed in the microstructure of a laser-processed metastable titanium–niobium alloy. Through transmission electron microscopy experiments, we reveal the microstructures with several metastable phase, among which is a novel orthorhombic phase found in Nb-lean regions that is fundamentally different from the expected$${\alpha }^{{\prime}{\prime}}$$ ${\alpha }^{\prime \prime }$orthorhombic phase. Second is the$${O}{\prime}$$ $O\prime$phase and the$${O}{\prime}$$ $O\prime$variant selection phenomenon in laser-processed metastable β-Ti alloys. Microstructural features were found to be highly sensitive to the processing history. We further examine the mechanisms behind these phase formations and discuss how these features can influence the properties of the alloy. 

Abstract Solomon rings, upholding the symbol of wisdom with profound historical roots, were widely used as decorations in ancient architecture and clothing. However, it was only recently discovered that such topological structures can be formed by self-organization in biological/chemical molecules, liquid crystals, etc. Here, we report the observation of polar Solomon rings in a ferroelectric nanocrystal, which consist of two intertwined vortices and are mathematically equivalent to a$${4}_{1}^{2}$$ $4_1^2$link in topology. By combining piezoresponse force microscopy observations and phase-field simulations, we demonstrate the reversible switching between polar Solomon rings and vertex textures by an electric field. The two types of topological polar textures exhibit distinct absorption of terahertz infrared waves, which can be exploited in infrared displays with a nanoscale resolution. Our study establishes, both experimentally and computationally, the existence and electrical manipulation of polar Solomon rings, a new form of topological polar structures that may provide a simple way for fast, robust, and high-resolution optoelectronic devices. 

Abstract The anomalous Hall effect (AHE) is a quantum coherent transport phenomenon that conventionally vanishes at elevated temperatures because of thermal dephasing. Therefore, it is puzzling that the AHE can survive in heavy metal (HM)/antiferromagnetic (AFM) insulator (AFMI) heterostructures at high temperatures yet disappears at low temperatures. In this paper, an unconventional high‐temperature AHE in HM/AFMI is observed only around the Néel temperature of AFM, with large anomalous Hall resistivity up to 40 nΩ cm is reported. This mechanism is attributed to the emergence of a noncollinear AFM spin texture with a non‐zero net topological charge. Atomistic spin dynamics simulation shows that such a unique spin texture can be stabilized by the subtle interplay among the collinear AFM exchange coupling, interfacial Dyzaloshinski–Moriya interaction, thermal fluctuation, and bias magnetic field.