Intrinsic Multiferroic in VNI Monolayer

Two-dimensional (2D) multiferroic materials, exhibiting both ferromagnetism and ferroelasticity, have promising applications in the miniaturization of quantum devices, such as high-density data storage and spintronic devices. Using first-principles calculations, we propose a 2D material, a ternary, vanadium–nitride–halide compound VNI. Its dynamic, mechanical, and thermal stabilities are confirmed by phonon spectrum, elastic modulus, and molecular dynamics simulations. The VNI monolayer is a robust ferromagnetic metal with a sizable in-plane magnetic anisotropic energy (153 μeV per V atom). Meanwhile, the monolayer has a moderate ferroelastic switching barrier of 100.66 meV/atom, which would facilitate the fast ferroelastic dynamics under external stress. Notably, the magnetic anisotropy axis of the VNI monolayer can be adjusted from the a-axis to the b-axis through reversible ferroelastic strain, exhibiting the characteristics of magnetoelastic coupling. These results shed light on the design of nonvolatile-memory devices

Multiferroicity in a Two-Dimensional Non-van der Waals Crystal of AgCr₂X₄ (X = S or Se)

Two-dimensional (2D) intrinsic multiferroics have long been pursued not only for their potential technological applications but also as model systems for studying emergent quantum phenomena and coupling mechanisms between various order parameters in low-dimensional space. However, the realization of 2D multiferroics is still a challenge. In this paper, we reveal that 2D AgCr2X4 (X = S or Se) crystals, which have been synthesized from the non-van der Waals (non-vdW) AgCrX2 bulk phase, are type I half-metallic/metallic multiferroics in which ferroelectricity and ferromagnetism coexist. The off-centering displacement of the Ag ion introduces out-of-plane polarization, and the magnetism originates from the interactions between Cr atoms. Remarkably, AgCr2Se4 shows topologically nontrivial spin textures, such as Meron pairs and Néel-type skyrmions, under suitable temperatures and magnetic fields. Our findings demonstrate that 2D multiferroics can be achieved from non-vdW materials and in turn open a new avenue for 2D multiferroics

Electric Field-Controlled Magneto-Optical Kerr Effect in A‑Type Antiferromagnetic Fe₂CX₂ (X = F, Cl) and Its Janus Monolayer

The magneto-optical Kerr effect (MOKE) is a powerful probe of magnetism and has recently gained new attention in antiferromagnetic (AFM) materials. Through extensive first-principles calculations and group theory analysis, we have identified Fe2CX2 (X = F, Cl) and Janus Fe2CFCl monolayers as ideal A-type collinear AFM materials with high magnetic anisotropy and Néel temperatures. By applying a vertical external electrical field (Ef) of 0.2 V/Å, the MOKE is activated for Fe2CF2 and Fe2CCl2 monolayers without changing their magnetic ground state, and the maximum Kerr rotation angles are 0.13 and 0.08°, respectively. Due to the out-of-plane spontaneous polarization, the intrinsic and nonvolatile MOKE is found in the Janus Fe2CFCl monolayer and the maximal Kerr rotation angle without external electronic field is 0.25°. Moreover, the intrinsic built-in electronic field also gives origin to more robust A-type AFM ordering and reversible Kerr angle against external Ef. Our study suggests that Ef is an effective tool for controlling MOKE in two-dimensional (2D) AFM materials. This research opens the possibility of related studies and applications in AFM spintronics

sj-docx-1-jmh-10.1177_15579883231189622 – Supplemental material for HIV/AIDS Knowledge, Depression, and HIV-Related Stigma Among Elderly Men in Rural China: A Hierarchical Regression Analysis

Supplemental material, sj-docx-1-jmh-10.1177_15579883231189622 for HIV/AIDS Knowledge, Depression, and HIV-Related Stigma Among Elderly Men in Rural China: A Hierarchical Regression Analysis by Qinxi Liu, Huan He, Qinying He, Na Li, Wei Xiao, Jie Xiao, Bihui Yang, Yuan Li and Yi Yang in American Journal of Men's Health</p

Room-Temperature Ferromagnetism in Epitaxial Bilayer FeSb/SrTiO₃(001) Terminated with a Kagome Lattice

Two-dimensional (2D) magnets exhibit unique physical properties for potential applications in spintronics. To date, most 2D ferromagnets are obtained by mechanical exfoliation of bulk materials with van der Waals interlayer interactions, and the synthesis of single- or few-layer 2D ferromagnets with strong interlayer coupling remains experimentally challenging. Here, we report the epitaxial growth of 2D non-van der Waals ferromagnetic bilayer FeSb on SrTiO3(001) substrates stabilized by strong coupling to the substrate, which exhibits in-plane magnetic anisotropy and a Curie temperature above 390 K. In situ low-temperature scanning tunneling microscopy/spectroscopy and density-functional theory calculations further reveal that an Fe Kagome layer terminates the bilayer FeSb. Our results open a new avenue for further exploring emergent quantum phenomena from the interplay of ferromagnetism and topology for application in spintronics