I10-Beamline for Advanced Dichroism - scattering
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Moritz
Winter
,
A.
Pignedoli
,
M. C.
Rahn
,
A. S.
Sukhanov
,
B.
Achinuq
,
J. R.
Bollard
,
M.
Azhar
,
K.
Everschor-Sitte
,
D.
Pohl
,
S.
Schneider
,
A.
Tahn
,
V.
Ukleev
,
M.
Valvidares
,
A.
Thomas
,
D.
Wolf
,
P.
Vir
,
T.
Helm
,
G.
Van Der Laan
,
T.
Hesjedal
,
J.
Geck
,
C.
Felser
,
B.
Rellinghaus
Diamond Proposal Number(s):
[28882]
Open Access
Abstract: Chiral soliton lattices (CSLs) emerge from the competition between Dzyaloshinskii–Moriya interaction, anisotropy, and magnetic fields. While well established in monoaxial helimagnets, their role in materials with anisotropic, direction-dependent chirality remains poorly understood. Here, we report the direct observation of a crossover from π to 2π soliton lattices in the non-centrosymmetric Heusler compound Mn1.4PtSn. Combining Lorentz transmission electron microscopy, resonant elastic X-ray scattering, and micromagnetic simulations, we identify a π-CSL as the magnetic ground state—rather than the expected spiral phase—which evolves into a classical 2π-CSL under increasing out-of-plane fields. This transition is governed by an interplay between uniaxial magnetocrystalline anisotropy and magnetostatic interactions, qualitatively captured by a double sine-Gordon model. Our framework extends to materials with D2d, S4, Cnv, or Cn symmetries in the thin-film limit, providing a unifying route to engineer magnetic phase diagrams in chiral systems with implications for soliton-based spintronics and topological transport.
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Aug 2026
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Abstract: Topological insulators become functional magnetic quantum materials once time-reversal symmetry is broken, enabling phenomena such as the quantum anomalous Hall effect and related chiral transport states. Over the past decade, we have pursued a systematic program to understand how magnetic order can be introduced, controlled, and quantitatively characterized in topological materials grown by molecular beam epitaxy. This contribution reviews our work on magnetic doping and magnetic proximity effects in (Bi,Sb)2 Te3based systems, with a particular emphasis on depth-resolved and local probes of magnetism. Using a combination of polarized neutron reflectometry, muon spin spectroscopy, and element-specific x-ray techniques, we have established where magnetic order resides, how homogeneous it is, and how it couples across interfaces. We show that magnetic doping often leads to intrinsically inhomogeneous magnetic states, while carefully engineered heterostructures can imprint or enhance magnetism in a controlled manner. Recent results on CrTe2/Bi2Te3 heterostructures provide direct evidence for proximity-induced magnetism in a topological insulator without chemical doping. Together, these studies demonstrate how neutrons and muons provide essential insight into magnetic topological materials and guide the design of platforms for quantum and spintronic devices.
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Jul 2026
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I10-Beamline for Advanced Dichroism - scattering
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Diamond Proposal Number(s):
[36751]
Abstract: The collective precession of magnetization manifests itself as magnon modes. These modes are governed by complex-valued vectorial eigenfunctions, which have remained experimentally challenging to observe. Here we introduce X-ray magnetic vector chronoscopy (XMVC), a time-resolved resonant scattering method that reconstructs the full magnetization dynamics with angular resolution of 0.1° (±0.01°). Applied to a synthetic antiferromagnetic multilayer (Si/NiFe (8 nm)/Ru (0.8 nm)/CoFeB (5.5 nm)), XMVC enables magnon state tomography, by directly measuring the nanoscale vectorial eigenfunctions of hybridized modes arising from magnon–magnon coupling. This approach provides full access to the system’s non-Hermitian Hamiltonian, revealing the complex-valued coupling strengths and non-orthogonal eigenbases. These results establish XMVC as an experimental platform for studying nanoscale spin systems by extracting the eigenfunctions of the system.
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May 2026
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NONE-No attached Diamond beamline
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Abstract: Antiferromagnets offer intrinsic stability against external magnetic fields, but this robustness also makes controlled manipulation of their spin structure challenging. Here we demonstrate that a thin ferromagnetic Co overlayer enables magnetic-field-induced reorientation of the Néel vector in NiO, mediated by strong interfacial coupling rather than conventional exchange bias. Using x-ray magnetic circular and linear dichroism, we show that the NiO spin structure partially aligns with the Co magnetization under applied fields, resulting in a direct correlation between ferromagnetic and antiferromagnetic domain patterns. Systematic variation of the Co thickness reveals a crossover between two distinct coupling regimes. For thin Co layers, NiO follows the Co magnetization during field cycling, whereas thicker Co layers exhibit conventional exchange bias, with NiO acting as a pinning layer. This crossover occurs at a Co thickness of approximately 3 nm, which marks the transition between inverse coupling and exchange-bias-dominated behavior.
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Apr 2026
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I10-Beamline for Advanced Dichroism - scattering
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Diamond Proposal Number(s):
[36751]
Abstract: Non-collinear spin textures, such as spin spirals and skyrmions, exhibit rich emergent physics in their spin dynamics. Nevertheless, the potential to utilize their distinctive spin resonance characteristics for on-chip microwave magnonic applications is rarely explored. Here we demonstrate microwave emission and mode coupling from the resonating spin spiral lattice in a Cu2OSeO3/Pt/NiFe heterostructure. We use time-resolved resonant elastic X-ray scattering to visualize the exact vectorial spin precession modes from the two magnetic species in real time. Our results show that the ferromagnetic NiFe layer dynamically captures the excitation modes of the conical order in helimagnet Cu2OSeO3. The off-resonance NiFe spin precession is phase locked to the helimagnet with a fixed offset, thereby presenting distinct chiral dynamics. This demonstrates that the magnons produced in the process—referred to as helimagnons—can wirelessly transmit spin information at gigahertz frequencies, opening new avenues for on-chip microwave magnonics.
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Jan 2026
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I10-Beamline for Advanced Dichroism - scattering
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S.
Pylypenko
,
Moritz
Winter
,
U. K.
Rößler
,
D.
Pohl
,
R.
Kyrychenko
,
Marein
Rahn
,
B.
Achinuq
,
J. R.
Bollard
,
P.
Vir
,
G.
Van Der Laan
,
T.
Hesjedal
,
J.
Schultz
,
B.
Rellinghaus
,
C.
Felser
,
A.
Lubk
Diamond Proposal Number(s):
[28882]
Open Access
Abstract: Disordered two-dimensional (2D) lattices, including hexatic and various glassy states, are observed in a wide range of 2D systems including colloidal nanoparticle assemblies and fluxon lattices. Their disordered nature determines the stability and mobility of these systems, as well as their response to the external stimuli. Here we report on the controlled creation and characterization of a disordered 2D lattice of nontopological magnetic bubbles in the noncentrosymmetric ferrimagnetic alloy Mn1.4PtSn. By analyzing the type and frequency of fundamental lattice defects, such as dislocations, the orientational correlation, as well as the induced motion of the lattice in an external field, a nonergodic glassy state, stabilized by directional application of an external field, is revealed.
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Dec 2025
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I10-Beamline for Advanced Dichroism - scattering
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Diamond Proposal Number(s):
[33454]
Open Access
Abstract: Magnetron sputtering offers a scalable route to magnetic topological insulators (MTIs) based on Cr-doped Sb2Te3. We combine a range of X-ray diffraction (XRD), reciprocal-space mapping (RSM), scanning transmission electron microscopy (STEM), scanning TEM-energy-dispersive X-ray spectroscopy (STEM-EDS), and X-ray absorption spectroscopy, and X-ray magnetic circular dichroism (XAS/XMCD) techniques to study the structure and magnetism of Cr-doped Sb2Te3 films. Symmetric 𝜃
-2𝜃
XRD and RSM establish a solubility window. Layered tetradymite order persists up to ∼10 at.-% Cr, while higher doping yields CrTe/Cr2Te3 secondary phases. STEM reveals nanocrystalline layered stacking at low Cr and loss of long-range layering at higher Cr concentrations, consistent with XRD/RSM. Magnetometry on a 6% film shows soft ferromagnetism at 5 K. XAS and XMCD at the Cr 𝐿2,3
edges exhibits a depth dependence: total electron yield (TE; surface sensitive) shows both nominal Cr2+ and Cr3+, whereas fluorescence yield (FY; bulk sensitive) shows a much higher Cr2+ weight. Sum rules applied to TEY give 𝑚𝐿=(0.20±0.04)
𝜇B
/Cr, and 𝑚𝑆=(1.6±0.2)
𝜇B
/Cr, whereby we note that the applied maximum field (3 T) likely underestimates 𝑚𝑆
. These results define a practical growth window and outline key parameters for MTI films.
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Oct 2025
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I10-Beamline for Advanced Dichroism - scattering
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Miming
Cai
,
Shangyuan
Wang
,
Yuelin
Zhang
,
Xiaoqing
Bao
,
Dekun
Shen
,
Jinghua
Ren
,
Lei
Qiu
,
Haiming
Yu
,
Zhenlin
Luo
,
Mathias
Kläui
,
Shilei
Zhang
,
Nicolas
Jaouen
,
Gerrit
Van Der Laan
,
Thorsten
Hesjedal
,
Ka
Shen
,
Jinxing
Zhang
Diamond Proposal Number(s):
[36632]
Abstract: Symmetry engineering is an effective approach for generating emergent phases and quantum phenomena. In magnetic systems, the Dzyaloshinskii-Moriya (DM) interaction is essential for stabilizing chiral spin textures. The symmetry manipulation of DM vectors, described in three dimensions, could provide a strategy toward creating abundant topologically magnetic phases. Here, we have achieved breaking the rotational and mirror symmetries of the three-dimensional DM vectors in a strongly correlated ferromagnet, which were directly measured through the nonreciprocal spin-wave propagations in both in-plane and out-of-plane magnetic field geometries. Combining cryogenic magnetic force microscopy and micromagnetic simulations, we discover a bimeron phase that emerges between the spin spiral and skyrmion phases under an applied magnetic field. Such an artificially manipulated DM interaction is shown to play a critical role in the formation and evolution of the large-area bimeron lattice, a phenomenon that could be realized across a broad range of materials. Our findings demonstrate that symmetry engineering of the DM vectors can be practically achieved through epitaxial strain, paving the way for the creation of diverse spin topologies and the exploration of their emergent functionalities.
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Sep 2025
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I10-Beamline for Advanced Dichroism - scattering
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Diamond Proposal Number(s):
[36644]
Open Access
Abstract: The synthesis and magnetic properties of the intrinsic magnetic topological insulator MnBi2Te4, grown by magnetron sputtering, are investigated. While this growth method enables smoother morphologies than molecular beam epitaxy and is compatible with scalable processing, the metastable nature of MnBi2Te4 presents considerable challenges in phase control and magnetic uniformity. By systematically varying the relative sputter powers of Mn, Bi2Te3, and Te targets, conditions that favor the formation of near-stoichiometric MnBi2Te4, as supported by X-ray diffraction, atomic force microscopy, and energy-dispersive X-ray spectroscopy, are identified. These films exhibit reduce surface roughness and lower twin-domain density compared to Mn-rich counterparts, which show evidence of phase separation and structural disorder. Magnetometry and X-ray magnetic circular dichroism reveal that both film types exhibit sizable Mn moments, although signatures of antiferromagnetic order are only weakly expressed and appear sensitive to composition and morphology. Despite producing structurally well-ordered films, clear linear dichroism attributable to A-type antiferromagnetic ordering is not observed, suggesting magnetic inhomogeneity or suppression of interlayer coupling. These results highlight the compositional sensitivity of sputtered MnBi2Te4 and underline the difficulties in stabilizing the intrinsic magnetic topological phase in thin-film form.
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Aug 2025
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Abstract: Resonant inelastic x-ray scattering (RIXS) is a powerful tool for probing the ground-state electronic configurations of actinide materials. However, in certain metallic uranium compounds, RIXS fails to detect excitations from the ground-state multiplet. This absence is attributed to strong hybridization between uranium 5𝑓 electrons and conduction electrons. In the present study, we extend RIXS investigations to a 16µg sample of the metallic compound AmFe2, marking an experiment at the 𝑀4,5 edges of a transuranium material. Americium in AmFe2 adopts a trivalent (Am3+) state with a 5𝑓6 electronic configuration having a 𝐽 = 0 ground state, with the 5𝑓 states located approximately 3 eV below 𝐸𝐹. The RIXS spectra exhibit well-resolved features that are in good agreement with theory. The localized nature of the 5𝑓 electrons in AmFe2 permits the observation of multiplet excitations despite its metallic character. These observations extend our understanding of RIXS in actinide systems.
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Aug 2025
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