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Abstract Emerging from the intricate interplay of topology and magnetism, the giant anomalous Hall effect (AHE) is the most known topological property of the recently discovered kagomé ferromagnetic Weyl semimetal Co₃Sn₂S₂with the magnetic Co atoms arranged on a kagomé lattice. Here it is reported that the AHE in Co₃Sn₂S₂can be fine‐tuned by an applied magnetic field orientated within ≈2° of the kagomé plane, while beyond this regime, it stays unchanged. Particularly, it can vanish in magnetic fields parallel to the kagomé plane and even decrease in magnetic fields collinear with the spin direction. This tunable AHE can be attributed to local spin switching enabled by the geometrical frustration of the magnetic kagomé lattice, revealing that spins in a kagomé ferromagnet change their switching behavior as the magnetic field approaches the kagomé plane. These results also suggest a versatile way to tune the properties of a kagomé magnet. 

Abstract 2D hybrid organic–inorganic perovskites (HOIPs) are commonly found under subcritical cyclic stresses and suffer from fatigue issues during device operation. However, their fatigue properties remain unknown. Here, the fatigue behavior of (C₄H₉‐NH₃)₂(CH₃NH₃)₂Pb₃I₁₀, the archetype 2D HOIP, is systematically investigated by atomic force microscopy (AFM). It is found that 2D HOIPs are much more fatigue resilient than polymers and can survive over 1 billion cycles. 2D HOIPs tend to exhibit brittle failure at high mean stress levels, but behave as ductile materials at low mean stress levels. These results suggest the presence of a plastic deformation mechanism in these ionic 2D HOIPs at low mean stress levels, which may contribute to the long fatigue lifetime, but is inhibited at higher mean stresses. The stiffness and strength of 2D HOIPs are gradually weakened under subcritical loading, potentially as a result of stress‐induced defect nucleation and accumulation. The cyclic loading component can further accelerate this process. The fatigue lifetime of 2D HOIPs can be extended by reducing the mean stress, stress amplitude, or increasing the thickness. These results can provide indispensable insights into designing and engineering 2D HOIPs and other hybrid organic–inorganic materials for long‐term mechanical durability. 

Abstract The dearth of suitable materials significantly restricts the practical development of infrared (IR) laser systems with highly efficient and broadband tuning. Recently, γ‐NaAsSe₂is reported, and it exhibits a large nonlinear second‐harmonic generation (SHG) coefficient of 590 pm V⁻¹at 2 µm. However, the crystal growth of γ‐NaAsSe₂is challenging because it undergoes a phase transition to centrosymmetric δ‐NaAsSe₂. Herein, the stabilization of non‐centrosymmetric γ‐NaAsSe₂by doping the As site with Sb, which results in γ‐NaAs_0.95Sb_0.05Se₂is reported. The congruent melting behavior is confirmed by differential thermal analysis with a melting temperature of 450 °C and crystallization temperature of 415 °C. Single crystals with dimensions of 3 mm × 2 mm are successfully obtained via zone refining and the Bridgman method. The purification of the material plays a significant role in crystal growth and results in a bandgap of 1.78 eV and thermal conductivity of 0.79 Wm⁻¹K⁻¹. The single‐crystal SHG coefficient of γ‐NaAs_0.95Sb_0.05Se₂exhibits an enormous value of |d₁₁| = 648 ± 74 pm V⁻¹, which is comparable to that of γ‐NaAsSe₂and ≈20× larger than that of AgGaSe₂. The bandgap of γ‐NaAs_0.95Sb_0.05Se₂(1.78 eV) is similar to that of AgGaSe₂, thus rendering it highly attractive as a high‐performing nonlinear optical material.