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Author Archives: Liu, Ronghua
News for our work about antiferromagnetic ordering enhanced magnetic damping in Mn2Au/CoFeB bilayers, recently published in APL
We published a paper entitled “Antiferromagnetic ordering enhanced magnetic damping in Mn2Au/CoFeB bilayers” in [Applied Physics Letters 129, 022401 (2026)]. Antiferromagnets hold significant potential for spintronic devices owing to their insensitivity to external magnetic fields and the absence of stray fields. In this work, we investigated the magnetic dynamics of Mn2Au/CoFeB bilayers via ferromagnetic resonance. We found that the Néel temperature of 2-nm-thick Mn2Au is as low as 40 K, in sharp contrast to that of bulk Mn2Au which exceeds 1000 K. As the temperature decreases from 160 to 10 K, the magnetic damping α of the CoFeB layer increases from 0.013 to 0.047, accompanied by a synchronous increase of the exchange coupling field. Such an enhancement of damping is attributed to the spin angular momentum transfer from CoFeB to Mn2Au, mediated by the AFM–FM exchange coupling which is strengthened by the antiferromagnetic ordering of Mn2Au at low temperatures. Our study provides deeper insights into AFM/FM dynamics and spintronic storage technology. Congratulations to Donghang Xie and co-workers!
News for our work about field-free perpendicular magnetization switching in Cu-doped BiSb topological insulators, recently published in PR Materials
We published a paper entitled “Copper-doped sputtered BiSb topological insulators for field-free perpendicular magnetization switching via out-of-plane spin polarization” in [Physical Review Materials 10, 064201 (2026)]. Achieving high SOT efficiency together with deterministic field-free switching is a key challenge for perpendicular-magnetization SOT-MRAM. In this work, we propose an effective strategy to realize high-efficiency field-free switching with an ultralow critical current density by doping copper into the topological insulator Bi0.9Sb0.1 (BiSb). The cosputtered Cu-BiSb alloy film achieves a high damping-like SOT efficiency (ξy,DL = 0.53) and, in contrast to undoped BiSb, a significant field-like torque induced by spin currents with out-of-plane spin polarization (ξz,FL = 0.55). This unconventional out-of-plane spin polarization enables deterministic field-free switching of perpendicular magnetization with a critical current density as low as ~4 MA/cm2 in Cu-BiSb/Pt/Co/Pt heterostructures. Our work provides critical support for the development of TI-based, high-performance and integrable SOT-MRAM devices. Congratulations to Haotian Duan and co-workers!
News for our work about high spin–orbit torque efficiency and robust thermal stability in topological BiSb/Pt bilayers, recently published in APL
We published a paper entitled “Achieving high spin–orbit torque efficiency and robust thermal stability in the sputter-grown topological bilayer BiSb/Pt” in [Applied Physics Letters 128, 212409 (2026)]. Topological insulators (TIs) are promising candidates for spin–orbit torque (SOT) devices owing to their high charge-to-spin conversion efficiency, but the SOT efficiency of sputtered TI films is usually compromised by the elevated thermal budgets required by CMOS back-end-of-line processing. In this work, we examined the thermal stability of sputter-grown Bi0.9Sb0.1/Py films. While the system exhibits a high SOT efficiency (ξFMR = 0.83) after annealing at 230 °C, the efficiency decreases by ~65% when the annealing temperature is increased to 400 °C. By inserting a 1.5 nm Pt layer at the Bi0.9Sb0.1/Py interface, interfacial intermixing is effectively suppressed, and the stack maintains a strong SOT efficiency of 0.85 even after annealing at 400 °C. These results pave the way for BiSb-based SOT-MRAM and its integration with CMOS technologies. Congratulations to Zui Tao, Zeyi Zhu (equal contribution) , and co-workers!!
News for our work about PINN for LLG dynamics, recently published in Progress in Physics
We published a paper entitled “Phase transition to failure: Quantifying critical thresholds of gradient conflict in PINN for LLG dynamics” (Chinese title: 从弱非线性可解到强非线性失效:LLG方程中梯度冲突诱导的PINN失效边界) in [ Progress in Physics 62(2), 309-322 (2026)]. In this work, we systematically investigated the capability of physics-informed neural networks (PINNs) for solving the Landau–Lifshitz–Gilbert (LLG) equation, the core governing equation of micromagnetics. By varying the magnetocrystalline anisotropy constant Ku and the demagnetization factor N to tune the strength of nonlinearity, we found that PINNs can solve the LLG equation only under weakly nonlinear conditions. In strongly nonlinear regimes, gradient conflicts during the training iterations lead to divergence or a catastrophic loss of accuracy, which defines a quantitative failure boundary for machine-learning solvers of nonlinear magnetization dynamics. This work provides a rational understanding of the performance boundaries of PINNs and helps to correct the overly optimistic assessment of ML-based differential-equation solvers. Congratulations to Ding Ma and Co-workers!
News for our work about subterahertz collective spin-resonance modes and field-adaptive reservoir computing in the chiral helimagnet Cr1/3TaS2, recently published in PR Applied
We published a paper entitled “Subterahertz collective spin-resonance modes and field-adaptive reservoir computing in the chiral helimagnet Cr1/3TaS2” in [Phys. Rev. Applied 24, 054022 (2025)]. Monoaxial chiral helimagnets (CHMs) host rich helical spin textures, including chiral soliton lattices (CSLs) with tunable periods. However, the spin resonance modes of existing CHMs lie in the gigahertz range, limiting their potential for high-speed signal processing. In this work, by combining ferromagnetic resonance, electron spin resonance, and magneto-Raman spectroscopy, we uncovered subterahertz CSL phonon modes in the CHM Cr1/3TaS2. Near the critical field, nontrivial CSL phonon modes reach 0.15 THz, while a uniform ferromagnetic resonance mode emerges at 0.375 THz in the forced ferromagnetic phase under 9 T. The CSL phonon frequency in Cr1/3TaS2 is five to six times higher than that of isostructural Cr1/3NbS2, owing to the larger spin–orbit-coupling-induced Dzyaloshinskii–Moriya interaction. Micromagnetic simulations further resolve the frequency spectrum and the spatial distributions of amplitudes, phases, and precession trajectories of each CSL resonance mode. Moreover, we demonstrate that physical reservoir computing exploiting the nonlinear collective spin dynamics and field-controlled hysteresis of these nontrivial spin textures achieves exceptional performance in time-series prediction tasks. Our findings pave the way for CHM materials toward subterahertz signal processing and neuromorphic computing applications. Congratulations to Zishuang Li, Shuai Zhang (equal contribution), and Co-workers!
News for our invited review on spin-based brain-like neuromorphic computing, recently published in Journal of Sichuan Normal University (Natural Science)
We published an invited review entitled “自旋类脑神经形态计算” (Spin-based Brain-like Neuromorphic Computing) in [Journal of Sichuan Normal University (Natural Science) 48(2), 176-191 (2025)]. Brain-inspired neuromorphic computing aims to simulate and implement the information processing and learning capabilities of the biological brain, with one of its key ideas being to mimic the behavior of biological neurons and synapses to achieve information transmission, processing, and storage. Owing to their non-volatility, high speed, low power consumption, nearly infinite endurance, and inherent nonlinearity, spintronic devices have been widely explored and have shown remarkable performance in neuromorphic computing. In this invited review, we systematically introduce and summarize various spintronic effects, including magnetoresistance effects, spin-transfer torque and spin-orbit torque effects, voltage-controlled magnetic anisotropy, and nonlinear magnetization dynamics. Taking the applications of various spintronic devices in reservoir computing, Ising machines, spiking neural networks, and true random number generators as examples, we present an outlook on the prospects and trends of spin-based neuromorphic computing hardware for future artificial-intelligence chips. Congratulations to Shuai Zhang and Co-workers!
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