Two-dimensional (2D) magnets hold promise for spintronics but still face challenges regarding limited magnetic tunability and air stability. Here, we demonstrate an effective oxygen plasma treatment strategy that simultaneously modulates magnetism and enhances the air stability of 1T-CrTe2 films. Microstructural characterizations reveal a depth-dependent progressive oxygen induced reconstruction process, in which oxygen substitution induces local Cr–Te–O structural rearrangements that are more pronounced near the surface and gradually extend toward the inner layers with increasing treatment duration. Theoretical calculations combined with magnetic measurements suggest that the effective oxidation level regulates interlayer magnetic coupling, leading to an evolution from a FiM-related step-like magnetic transition behavior to a FM-dominated magnetic response. Significantly, the oxygen-doped 1T-CrTe2 exhibits robust environmental stability, retaining room-temperature magnetism even after long-term ambient exposure. This work presents a dual-purpose approach for engineering robust, tunable 2D materials for future spintronic applications.
The research about two-dimensional van der Waals magnetic materials has advanced the 22 breakthroughs in ultrathin magnetic devices. We experimentally demonstrate that single-crystal 23 N-face AlN polar substrate can program layer-number-parity-dependent magnetic multistates and 24 their evolution sequence in few-layer CrI3. In odd-layer samples, as 5L-CrI3/AlN, when μ0H 25 sweeps from 3 to −3 T, the reflective magnetic circular dichroism signal evolves through distinct 26 magnetic multistates (+5 → –1 → +1 → –5), where +1 corresponds to the moment of a spin-up 27 monolayer. Thereby, we vertically program novel magnetic ground states and their evolution 28 sequence via a simplified heterointerface. Our first-principles calculations attribute this effect to 29 interfacial hole doping: it globally reconfigures the magnetic ground state of odd-layer CrI3 to a 30 novel ferrimagnetic order, and spatially differentiates the interlayer exchange and magnetic 31 anisotropy between the surface/interfacial and interior layers. Our work advances the practical 32 integration and design of two-dimensional magnetic devices with tailored functionalities.
Information units are progressively approaching the fundamental physical limits of the integration density, including in terms of extremely small sizes, multistates and probabilistic traversal. However, simultaneously encompassing all of these characteristics in a unit remains elusive. Here, via real-time in situ electrical monitoring, we clearly observed stochastic alterations of multiple conductance states in Sc2C2@C88. The true random bit sequence generated exhibited an autocorrelation function whose confidence interval fell within ±0.02, demonstrating high-quality randomness. The alterations of multiple conductance states are controllable, that is, whose probability distributions could traverse from “0” to “1”, enabling us to factorize 551 into its prime factors. Furthermore, we proposed a matrix-chain multiplication scheme and experimentally verified the multiplication of two 4 × 4 state-transition matrices with a small maximum error < 0.05. Combined with theoretical calculations, the stochastic but controllable multistates are probably attributed to the rich energy landscape, which could be stepwise changed by the electric field. Our findings reveal extremely small multi-level probabilistic bit for matrix multiplication, which pave the way for ultracompact intelligent electronic devices.
Xiangqi Wang†, Cong Wang†, Yupeng Wang†, Chunhui Ye, Azizur Rahman, Min Zhang, Suhan Son, Jun Tan*, Zengming Zhang*, Wei Ji*, Je-Geun Park6,7,8, and Kai-Xuan Zhang†*
Abstract:
Van der Waals (vdW) magnets, with their two-dimensional (2D) atomic structures, provide a unique platform for exploring magnetism at the nanoscale. Although there have been numerous reports on their diverse quantum properties, the emergent interfacial magnetism— artificially created at the interface between two layered magnets—remains largely unexplored. This work presents observations of such emergent interfacial magnetism at the ferromagnet/antiferromagnet interface in a vdW heterostructure. We report the discovery of an intermediate Hall resistance plateau in the anomalous Hall loop, indicative of emergent interfacial antiferromagnetism fostered by the heterointerface. This plateau can be stabilized and further manipulated under varying pressures but collapses under high pressures over 10 GPa. Our theoretical calculations reveal that charge transfer at the interface is pivotal in establishing the interlayer antiferromagnetic spin-exchange interaction. This work illuminates the previously unexplored emergent interfacial magnetism at a vdW interface comprised of a ferromagnetic metal and an antiferromagnetic insulator, and highlights its gradual evolution under increasing pressure. These findings enrich the portfolio of emergent interfacial magnetism and pave the way for future investigations on vdW magnetic interfaces and the development of next-generation spintronic devices.
Two-dimensional room-temperature ferromagnet CrTe2 is a promising candidate material for spintronic applications. However, its large-scale and cost-effective synthesis remains a challenge. Here, we report the fine controllable synthesis of wafer-scale 1T-CrTe2 films on a SiO2/Si substrate using plasma-enhanced chemical vapor deposition at temperatures below 400 ºC. Magnetic hysteresis measurements reveal that the synthesized 1T-CrTe2 films exhibit perpendicular magnetic anisotropy along with distinct step-like magnetic transitions. We find that 1T-CrTe2 is susceptible to oxygen adsorption even in ambient conditions. Our theoretical calculations indicate that the oxidation of surface layers is crucial for the absence of out-of-plane easy axis in few-layer CrTe2, while the interlayer antiferromagnetic coupling among the upper surface layers leads to the observed step-like magnetic transitions. Our study provides a Si-CMOS compatible approach for the fabrication of magnetic two-dimensional materials and highlights how unintentional adsorbents or dopants can significantly influence the magnetic behaviors of these materials.
