I10-Beamline for Advanced Dichroism - scattering
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Diamond Proposal Number(s):
[36197]
Abstract: Heterostructures composed of heavy metal and van der Waals (vdW) magnets serve as platforms to investigate magnetotransport properties, enabling the electric readout of the spin-flop transition in the vdW antiferromagnet. We investigate the spin and orbital contributions to magnetism in Pt/exfoliated multilayer CrPS4 heterostructure using the synchrotron-radiation based x-ray magnetic circular dichroism technique measured in the total electron yield (TEY) mode. The TEY detection, with probing depth of 5–10 nm, mainly reflects the interfacial magnetic behavior near the Pt/CrPS4 boundary. A spin-flop transition appears near 0.7 T in both the CrPS4 single crystal and the Pt/CrPS4 heterostructures. The total Cr moment remains ∼2 μB/f.u. in both systems at 14 T and 6 K. In Pt/CrPS4, the orbital moment is strongly modulated by Pt, as manifested in the enhancement from ∼0.1 μB/f.u. in CrPS4 to ∼0.5 μB/f.u. in Pt/CrPS4, an effect attributable to the strong spin–orbit coupling with Pt. At 25 K, the total Cr moment reduces to ∼1.1 μB/f.u. in both systems. The Cr orbital moment in CrPS4 remains low ∼0.1 μB/f.u., whereas in Pt/CrPS4 it remains high ∼0.5 μB/f.u. These findings provide qualitative evidence of robust spin–orbit coupling and orbital hybridization at Pt/CrPS4 interface, and highlight the potential of heavy metal/vdW antiferromagnet heterostructures for spin-orbitronic device applications.
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Feb 2026
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I10-Beamline for Advanced Dichroism - scattering
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Jiahao
Liu
,
Xingtai
Chen
,
Jiaqi
Lu
,
Weixiang
Li
,
Zhaochun
Liu
,
Yongzhuo
Zhang
,
Peter
Bencok
,
Paul
Steadman
,
Wenqing
Liu
,
Weisheng
Zhao
,
Shouzhong
Peng
Diamond Proposal Number(s):
[36197]
Open Access
Abstract: Exchange bias fields at antiferromagnet/ferromagnet (AFM/FM) interfaces play a crucial role in the performance of spintronic devices. Despite extensive research, the physical origin of exchange bias remains incompletely understood. In this study, we conduct a detailed investigation of a prototype AFM/FM interface widely used in spintronic applications, i.e., the IrMn/CoFeB interface. High-resolution synchrotron X-ray measurements reveal the existence of uncompensated Mn spins at the interface. While most of these spins are strongly coupled to the adjacent CoFeB layer, a small fraction remains pinned to the underlying IrMn underlayer. Element-specific X-ray magnetic circular dichroism hysteresis loops show that these pinned spins can be switched by increasing the annealing magnetic field. Furthermore, micromagnetic simulations indicate that an imbalance in the quantity of antiparallel pinned spins contributes to the observed variation in exchange bias. Overall, these findings offer important insights into the microscopic mechanisms governing exchange bias and its tunability.
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Jan 2026
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I10-Beamline for Advanced Dichroism - scattering
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Open Access
Abstract: Transition-metal doped topological insulators have been widely explored since the observation of quantum anomalous Hall effect (QAHE). Subsequently, the magnetic (Pb,Sn)(Te,Se) was predicted to possibly possess a high-temperature QAHE state. However, the fundamental understanding of Cr-doping-induced ferromagnetism in this system remains unclear. Here, we report the stable ferromagnetism in the high-crystalline Cr-doped SnTe films. Upon Cr doping, the magnetoconductance unveils a crossover from weak antilocalization to weak localization. Further increasing the Cr concentration to Cr0.17Sn0.83Te introduces a strong ferromagnetism with a Curie temperature of ~140 K. We detected a sizable spin moment ms = 2.28 ± 0.23 μB/Cr and a suppressed orbital moment ml = 0.02 μB/Cr. Cr dopants prefer to substitute the Sn sites and behave as divalent cations, as indicated by the experimental results and density function theory calculations. The controllable growth of magnetic SnTe thin films provides enlightenment towards the high-temperature QAHE in magnetic TCIs for the desired dissipationless transport in electronics.
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Jul 2024
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I10-Beamline for Advanced Dichroism - scattering
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Abstract: Intrinsic magnetic topological insulators (MTIs) have proven to be an important material system for the study of quantum effects and the development of novel electronic devices. Unlike the magnetically doped topological insulators (TIs)., intrinsic MTIs well preserve the crystalline ordering and homogeneity of the pristine TIs, leading to enhanced quantum coherency in many cases. Here, we report a detailed study of the atomic scale spin (ms) and orbital (m1) moments of an epitaxial MnBi2Te◃ thin film. The synchrotron-based x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) measurements were performed to investigate the electronic and magnetic properties of the thin film at 3 K and up to 14 T. The 16.3 nm MnBi2Te4/A12O2 shows reduced moments of ms=(1.64±0.2)μB/Mn and m1=(0.16±0.02)μB/Mn at 14 T compared to their bulk counterparts. The reduced magnetic moments may be attributed to the weakened intralayer or interlayer exchange interaction and the intrinsic structural defects of the materials. Future work to understand the correlations between the structural defects, intralayer or interlayer exchange interactions, and magnetic properties will have strong implications for both fundamental physics and practical applications of the MnBi2Te4 materials.
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May 2024
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I10-Beamline for Advanced Dichroism - scattering
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Ruifeng
Wang
,
Xingtai
Chen
,
Pengfei
Yan
,
Yongkang
Xu
,
Yilin
Zhang
,
Jin
Wang
,
Raymond
Fan
,
Peter
Bencok
,
Paul
Steadman
,
Yao
Li
,
Wenqin
Zou
,
Yongbing
Xu
,
Ronghua
Liu
,
Wenqing
Liu
,
Liang
He
Diamond Proposal Number(s):
[29054]
Abstract: The saturated magnetization (mtot) and the Gilbert damping constant (α) are the two key factors that determine the critical current density of the magnetization reversal in the spin-transfer-torque magnetic memory devices. Here, this study demonstrates the efficient modulation of these two parameters by tunning the composition of the Heusler Co3–xFexAl thin films, utilizing the x-ray magnetic circular dichroism technique and ferromagnetic resonance measurements. With the increase in Fe concentration, the mtot shows a downward trend mainly resulting from the decrease in Fe local magnetic moment instead of Co. On the other hand, the ultralow α decreases from 0.004 to 0.0012. This has been attributed to the reduction in the spin–orbit coupling, which is corroborated by the decrease in the orbit-to-spin moment ratio. Our findings add a building block for the Heusler compounds with tunable Gilbert damping and appropriate magnetization and show great potential in spintronic applications.
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Jul 2023
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I10-Beamline for Advanced Dichroism - scattering
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Zihan
Li
,
Shanshan
Liu
,
Jiabao
Sun
,
Jiayi
Zhu
,
Yanhui
Chen
,
Yunkun
Yang
,
Linfeng
Ai
,
Enze
Zhang
,
Ce
Huang
,
Pengliang
Leng
,
Minhao
Zhao
,
Xiaoyi
Xie
,
Yuda
Zhang
,
Nesta Benno
Joseph
,
Rajdeep
Banerjee
,
Awadhesh
Narayan
,
Jin
Zou
,
Wenqing
Liu
,
Xiaodong
Xu
,
Faxian
Xiu
Diamond Proposal Number(s):
[22532]
Abstract: Two-dimensional (2D) magnets offer valuable electrical and mechanical properties, and could be used to create 2D nanoelectromechanical systems. However, the low Curie temperature of most 2D magnets limits practical applications. Here we report van der Waals ferromagnetic low-pass filters based on wafer-scale iron germanium telluride (Fe5+xGeTe2) thin films grown by molecular-beam epitaxy. We show that the Curie temperature of the Fe5+xGeTe2 system can be continuously modulated from 260 to 380 K via in situ iron doping. Few-layer Fe5+xGeTe2 is used to fabricate planar spiral inductors, with the 2D magnetic core providing inductance enhancement of 74% at room temperature compared with an inductor without the core. Low-pass Butterworth filters are then created from inductance–capacitance circuits built with these inductors. The filters offer a broad dynamic range of around 40 dB, and the –3 dB cut-off frequency can be tuned from 18 to 30 Hz by using different inductors in the inductance–capacitance circuit.
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Mar 2023
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I10-Beamline for Advanced Dichroism - scattering
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Sheng
Jiang
,
Zhaocong
Huang
,
Qi
An
,
Wen
Zhang
,
Yuli
Yin
,
Dong
Zhang
,
Jun
Du
,
Biao
You
,
Jian-Guo
Zheng
,
Wenqing
Liu
,
Ya
Zhai
Abstract: The significance of spin transport over an interface in energy-efficient spintronic devices has stimulated interest in the spintronic society during the last few decades. Here, interfaces of
permalloy
/
Cu
1
−
x
Tb
x
(Py/Cu-Tb) were investigated in depth. As the Cu-Tb thickness increases, we found that the saturation magnetization of the bilayers falls and then plateaus. Element-specific x-ray magnetic circular dichroism studies suggest that the Tb moment aligns opposite to the Fe and Ni moments, forming a self-assembled antiferromagnetic interface. As a result, the Cu-Tb adjacent layer to Py and the interface have a significant impact on spin transport. Relevant parameters, such as spin mixing conductance, spin diffusion length, and damping, can be tuned by inserting a thin Cu layer between Py and Tb or varying the compositions of Cu-Tb alloys. Using rare-earth Tb, we provide an effective method for controlling the spin transport and magnetism of ferromagnet/normal-metal interfaces. This approach is expected to have a great deal of potential in spintronic applications.
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May 2022
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I10-Beamline for Advanced Dichroism - scattering
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Xiaoqian
Zhang
,
Wenqing
Liu
,
Wei
Niu
,
Qiangsheng
Lu
,
Wei
Wang
,
Ali
Sarikhani
,
Xiaohua
Wu
,
Chunhui
Zhu
,
Jiabao
Sun
,
Mitchel
Vaninger
,
Paul. F.
Miceli
,
Jianqi
Li
,
David J.
Singh
,
Yew San
Hor
,
Yue
Zhao
,
Chang
Liu
,
Liang
He
,
Rong
Zhang
,
Guang
Bian
,
Dapeng
Yu
,
Yongbing
Xu
Diamond Proposal Number(s):
[22532]
Abstract: One of the most promising avenues in 2D materials research is the synthesis of antiferromagnets employing 2D van der Waals (vdW) magnets. However, it has proven challenging, due in part to the complicated fabrication process and undesired adsorbates as well as the significantly deteriorated ferromagnetism at atomic layers. Here, the engineering of the antiferromagnetic (AFM) interlayer exchange coupling between atomically thin yet ferromagnetic CrTe2 layers in an ultra-high vacuum-free 2D magnetic crystal, Cr5Te8 is reported. By self-introducing interstitial Cr atoms in the vdW gaps, the emergent AFM ordering and the resultant giant magnetoresistance effect are induced. A large negative magnetoresistance (10%) with a plateau-like feature is revealed, which is consistent with the AFM interlayer coupling between the adjacent CrTe2 main layers in a temperature window of 30 K below the Néel temperature. Notably, the AFM state has a relatively weak interlayer exchange coupling, allowing a switching between the interlayer AFM and ferromagnetic states at moderate magnetic fields. This work represents a new route to engineering low-power devices that underpin the emerging spintronic technologies, and an ideal laboratory to study 2D magnetism.
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May 2022
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I10-Beamline for Advanced Dichroism - scattering
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Diamond Proposal Number(s):
[16538]
Open Access
Abstract: As an emerging class of two-dimensional (2D) materials, van der Waals (vdW) magnets have attracted a lot of research attention since they can give access to fundamental physics and potential spintronic device applications. Among these 2D vdW magnets, CrSiTe3, as an intrinsic ferromagnetic semiconductor, exhibits great potentials in low-dimensional spintronics. Of particular interest in this 2D vdW magnet is the electronic and magnetic properties at the atomic-scale, which has yet been fully explored so far. Here, combing angle-resolved photoemission spectroscopy, bulk magnetic measurements, and synchrotron-based x-ray techniques, an unambiguous picture of the electronic and magnetic states of CrSiTe3 is presented. Hybridization of Cr-3d and Te-5p orbitals and the semiconducting behavior are confirmed by the band structure detection. Intrinsic ferromagnetism with a magnetic anisotropy constant of 1.56 × 105 erg/cm3 is attributed to the superexchange interaction of the Cr3+ ions. In addition, temperature-dependent spin and orbital moments are determined, and a fitted critical exponent of 0.169 implies that CrSiTe3 is in good agreement with the 2D Ising model. More remarkably, unquenched orbital moments are experimentally evidenced, bringing CrSiTe3 with orbital-dependent intriguing effects and great potentials toward the spintronic devices.
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Oct 2021
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I10-Beamline for Advanced Dichroism - scattering
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Shanshan
Liu
,
Zihan
Li
,
Ke
Yang
,
Enze
Zhang
,
Awadhesh
Narayan
,
Xiaoqian
Zhang
,
Jiayi
Zhu
,
Wenqing
Liu
,
Zhiming
Liao
,
Masaki
Kudo
,
Takaaki
Toriyama
,
Yunkun
Yang
,
Qiang
Li
,
Linfeng
Ai
,
Ce
Huang
,
Jiabao
Sun
,
Xiaojiao
Guo
,
Wenzhong
Bao
,
Qingsong
Deng
,
Yanhui
Chen
,
Lifeng
Yin
,
Jian
Shen
,
Xiaodong
Han
,
Syo
Matsumura
,
Jin
Zou
,
Yongbing
Xu
,
Xiaodong
Xu
,
Hua
Wu
,
Faxian
Xiu
Diamond Proposal Number(s):
[20748]
Open Access
Abstract: Two-dimensional (2D) ferromagnetic materials have been discovered with tunable magnetism and orbital-driven nodal-line features. Controlling the 2D magnetism in exfoliated nanoflakes via electric/magnetic fields enables the boosted Curie temperature (TC) or phase transitions. One of the challenges, however, is the realization of high TC 2D magnets that are tunable, robust and suitable for large scale fabrication. Here, we report molecular-beam epitaxy growth of wafer-scale Fe3+XGeTe2 films with TC above-room-temperature. By controlling the Fe composition in Fe3+XGeTe2, a continuously-modulated TC in a broad range of 185–320 K has been achieved. This widely tunable TC is attributed to the doped interlayer Fe that provide a 40% enhancement around the optimal composition X = 2. We further fabricated magnetic tunneling junction device arrays that exhibit clear tunneling signals. Our results show an effective and reliable approach, i.e. element doping, to produce robust and tunable ferromagnetism beyond room temperature in a large-scale 2D Fe3+XGeTe2 fashion.
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Jul 2021
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