arXiv subjects

Xinhou Chen

Publications and source records attributed to Xinhou Chen.

6 recordsLinked to original sources

arXiv2026

All-electric picosecond field-free spin-orbit torque switching in magnetic trilayers

Spin-orbit torque (SOT) enables the electrical manipulation of the magnetization with high speed and low energy consumption for magnetic random-access memory (MRAM) applications. Previous studies of short-pulse SOT switching have mainly focused on the nanosecond regime, whereas reports employing picosecond pulses remain scarce and have largely relied on field-assisted switching using bulky, high-power laser systems, limiting prospects for chip-level integration. Here, we introduce an all-electrical on-chip nanoplasma pulse generator capable of producing pulses as short as 6.4 ps, enabling ultrafast picosecond field-free SOT switching in magnetic trilayers. We show that reducing the pulse width lowers the writing energy by 2-3 orders of magnitude, with ultrafast Joule heating assistance playing an essential role in the enhanced efficiency of the picosecond regime. Our demonstration of ultrafast, all-electrical, and field-free SOT switching establishes the nanoplasma pulse generator as an on-chip platform for ultrafast spintronic studies, with promise for high-speed, energy-efficient, and scalable SOT-MRAM technologies.

cond-mat.mtrl-sci↗

arXiv2026

Controlling Terahertz Spintronic Photocurrents in 2D-Semiconductor|Ferromagnet Heterostructures through a Functional Hybrid Interface

A profound understanding of terahertz (THz) spin and charge currents in heterostructures involving ferromagnets (FMs) and two-dimensional (2D) materials promises emerging applications in high-speed sensing and data processing. Yet, ultrafast experimental insights remain very limited. Here, we study the efficient photo-generation of THz spin and charge currents in bilayers made from the transition-metal dichalcogenide (TMD) MoS2 and the FM Co. We find that the efficiency of current generation strongly depends on the pump photon energy, as previously reported. Surprisingly, however, we observe that the current dynamics remain identical for pump photon energies above and below the MoS2 band gap. Supported by ab-initio calculations, we conclude that an interfacial hybrid metallic layer forms at the MoS2/Co boundary that has a pronounced photon-energy-dependent absorptance. Thus, the hybrid interfacial layer effectively acts like a pump-energy transducer that increases the spin-current generated in the nearby Co. Our results uncover the vital role of interfacial hybridization as a yet unexplored mechanism for efficient generation of ultrafast photocurrents in 2D-TMD|FM structures.

cond-mat.mes-hall↗

arXiv2026

Observation of magnon torques mediated by orbital hybridization at the light metal/antiferromagnetic insulator interface

Magnon torques, which can operate without involving moving electrons, could circumvent the Joule heating issue. In conventional magnon torque systems, the spin source layer with strong spin-orbit coupling is utilized to inject magnons, and the efficiency is limited by the inherent spin Hall conductivity of the spin source layer. In this work, we observe magnon torques in the Cr/NiO/ferromagnet heterostructure with the effective spin Hall conductivity of 2.45x10^5 hbar/(2e{\Omega}m), twice that of the best conventional magnon torque system. We demonstrate the magnon-torque-driven switching of a perpendicularly magnetized CoFeB layer at room temperature, with a switching power consumption density of 0.136 mW/{\mu}m^2. We find that the magnon torque originates from the orbital hybridization and interfacial inversion symmetry breaking at the Cr/NiO interface. Our findings not only significantly enhance the efficiency of magnon torques, but also provide key insights into the fundamental mechanisms of magnon injections.

cond-mat.mtrl-sci↗

arXiv2026

Bio-resorbable magnetic tunnel junctions

Magnetic tunnel junctions (MTJs) play a crucial role in spintronic applications, particularly data storage and sensors. Especially as a non-volatile memory, MTJs have received substantial attention due to its CMOS compatibility, low power consumption, fast switching speed, and high endurance. In parallel, bio-resorbable electronics have emerged as a promising solution for systems requiring temporary operation and secure data disposal, especially in military, intelligence, and biomedical systems where devices must safely disintegrate under physiological conditions. In this study, we investigate the bio-resorbability of MTJ by analyzing the dissolution behavior of its nanometer-thick constituent layers in phosphate-buffered saline (PBS) solution at pH 7.4, simulating physiological environments. The MTJ structures, composed of bio-resorbable materials, exhibit well-controlled degradation behaviors. Critically, as one of the ferromagnetic layers dissolves, binary information is irreversibly lost, within 10 hours of immersion. These findings highlight the potential of MTJs not only as high-performance memory elements but also as secure, transient data storage platforms. The ability to modify the dissolution lifetime by materials and thickness selection offers unique advantages for short-lived implantable devices, paving the way for integrating spintronic functionality into next-generation bioresorbable electronics.

cond-mat.mtrl-sci↗

arXiv2026

Crystalline-dependent magnon torques in all-sputtered Hf/Cr2O3/ferromagnet heterostructures

Electron motion in spin-orbit torque devices inevitably leads to the Joule heating issue. Magnon torques can potentially circumvent this issue, as it enables the transport of spin angular momentum in insulating magnetic materials. In this work, we fabricate a sandwich structure composed of Hf/antiferromagnetic Cr2O3/ferromagnet and demonstrate that the magnon torque is strongly dependent on the crystalline structure of Cr2O3. Magnon torques are stronger when the Neel vector of Cr2O3 aligns parallel to the spin polarization generated in Hf, while they are suppressed when the Neel vector is perpendicular to the spin polarization. The magnon torque efficiency is estimated to be -0.134 using in-plane second harmonic Hall measurements. Using magnon torques, we achieve perpendicular magnetization switching of CoFeB, with a critical switching current density of 4.09 x 10^7 A/cm^2. Furthermore, the spin angular momentum loss due to the insertion of Cr2O3 is found to be lower than that of polycrystalline NiO. Our work highlights the role of antiferromagnet crystalline structures in controlling magnon torques, broadening the potential applications of magnon torques.

cond-mat.mtrl-sci↗

arXiv2020

Generation and manipulation of chiral terahertz waves emitted from the three-dimensional topological insulator Bi2Te3

Arbitrary manipulation of broadband terahertz waves with flexible polarization shaping at the source has great potential in expanding real applications such as imaging, information encryption, and all-optically coherent control of terahertz nonlinear phenomena. Topological insulators featuring unique spin-momentum locked surface state have already exhibited very promising prospects in terahertz emission, detection and modulation, which may lay a foundation for future on-chip topological insulator-based terahertz systems. However, polarization shaped terahertz emission with prescribed manners of arbitrarily manipulated temporal evolution of the amplitude and electric-field vector direction based on topological insulators have not yet been explored. Here we systematically investigated the terahertz radiation from topological insulator Bi2Te3 nanofilms driven by femtosecond laser pulses, and successfully realized the generation of efficient chiral terahertz waves with controllable chirality, ellipticity, and principle axis. The convenient engineering of the chiral terahertz waves was interpreted by photogalvanic effect induced photocurrent, while the linearly polarized terahertz waves originated from linear photogalvanic effect induced shift currents. We believe our works not only help further understanding femtosecond coherent control of ultrafast spin currents in light-matter interaction but also provide an effective way to generate spin-polarized terahertz waves and accelerate the proliferation of twisting the terahertz waves at the source.

physics.optics↗