I10-Beamline for Advanced Dichroism - scattering
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Diamond Proposal Number(s):
[38593]
Open Access
Abstract: Non-collinear magnetism is of high interest in the field of magnetoelectrics supplying a convenient mechanism to break inversion symmetry and thereby allowing for a spontaneous electrical polarization. Such “multiferroics of spin origin” are inherently suitable for electric field control of magnetism, offering a route toward low power ICT applications. This study presents element specific evidence for a non-collinear magnetic structure in the single crystal M-type hexaferrite mathematical equation based on vibrating sample magnetometry (VSM) and resonant soft X-ray diffraction (RSXD) measurements. Whilst the Co-Ti substitution is key to transforming the parent compound (mathematical equation) from a uniaxial collinear magnet to one with conical order at room temperature, the magnetic moments on the mathematical equation ions, within the detection limit, do not contribute to the periodic non-collinear order, which is primarily driven by the Fe moments.
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Dec 2025
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B16-Test Beamline
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Open Access
Abstract: A multi-strip detector made of synthetic single crystal diamond (SCD), based on a p-type/intrinsic diamond/Schottky metal transverse configuration and operating at zero bias voltage, was developed for imaging from extreme UV (EUV) to soft X-rays. The photodetector was patterned with 32 strips made of boron-doped diamond directly deposited, by means of the CVD technique and the standard lithographic technique, on top of the HPHT diamond growth substrate. The width of each strip and the gap between two adjacent strips were 100 μm and 20 μm, respectively. The strips were embedded in intrinsic SCD of an active area of 3.2 × 2.5 mm2, also deposited using the CVD technique in a separate growing machine. In the present structure, the prototype photodetector is suitable for 1D imaging. However, all the dimensions above can be varied depending on the applications. The use of p-type diamond strips represents an attempt to mitigate the photoelectron emission from metal contacts, a non-negligible problem under EUV irradiation. The detector was tested with UV radiation and soft X-rays. To test the photodetector as an imaging device, a headboard (XDAS-DH) and a signal processing board (XDAS-SP) were used as front-end electronics. A standard XDAS software was used to acquire the experimental data. The results of the tests and the detector’s construction process are presented and discussed in the paper.
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Oct 2025
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I10-Beamline for Advanced Dichroism - scattering
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Guangchao
Li
,
Christopher
Foo
,
Raymond
Fan
,
Mingji
Zheng
,
Qiang
Wang
,
Yueying
Chu
,
Jiasi
Li
,
Sarah
Day
,
Paul
Steadman
,
Chiu
Tang
,
Tsz Woon Benedict
Lo
,
Feng
Deng
,
Shik Chi Edman
Tsang
Diamond Proposal Number(s):
[24677]
Abstract: The distribution of substitutional aluminum (Al) atoms in zeolites affects molecular adsorbate geometry, catalytic activity, and shape and size selectivity. Accurately determining Al positions has been challenging. We used synchrotron resonant soft x-ray diffraction (RSXRD) at multiple energies near the Al K-edge combined with molecular adsorption techniques to precisely locate “single Al” and “Al pairs” in a commercial H-ZSM-5 zeolite. This analysis depicts three distinct Al tetrahedral (T) sites: T8, T6, and T4. A combined suite of characterizations, including ammonia temperature-dependent desorption, neutron powder diffraction, solid-state nuclear magnetic resonance spectroscopy, and density functional theory calculations, reveal isolated ammonia adsorption on T8 as “single Al” in the straight channel and bridged ammonia adsorption on T6 and T4 as an “Al pair” (AlT6-O-SiT5-O-AlT4) in the straight-sinusoidal intersection.
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Jan 2025
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I06-Nanoscience (XPEEM)
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Allan S.
Johnson
,
Daniel
Perez-Salinas
,
Khalid M.
Siddiqui
,
Sungwon
Kim
,
Sungwook
Choi
,
Klara
Volckaert
,
Paulina E.
Majchrzak
,
Soeren
Ulstrup
,
Naman
Agarwal
,
Kent
Hallman
,
Richard F.
Haglund
,
Christian M.
Günther
,
Bastian
Pfau
,
Stefan
Eisebitt
,
Dirk
Backes
,
Francesco
Maccherozzi
,
Ann
Fitzpatrick
,
Sarnjeet S.
Dhesi
,
Pierluigi
Gargiani
,
Manuel
Valvidares
,
Nongnuch
Artrith
,
Frank
De Groot
,
Hyeongi
Choi
,
Dogeun
Jang
,
Abhishek
Katoch
,
Soonnam
Kwon
,
Sang Han
Park
,
Hyunjung
Kim
,
Simon E.
Wall
Diamond Proposal Number(s):
[22048]
Open Access
Abstract: Using light to control transient phases in quantum materials is an emerging route to engineer new properties and functionality, with both thermal and non-thermal phases observed out of equilibrium. Transient phases are expected to be heterogeneous, either through photo-generated domain growth or by generating topological defects, and this impacts the dynamics of the system. However, this nanoscale heterogeneity has not been directly observed. Here we use time- and spectrally resolved coherent X-ray imaging to track the prototypical light-induced insulator-to-metal phase transition in vanadium dioxide on the nanoscale with femtosecond time resolution. We show that the early-time dynamics are independent of the initial spatial heterogeneity and observe a 200 fs switch to the metallic phase. A heterogeneous response emerges only after hundreds of picoseconds. Through spectroscopic imaging, we reveal that the transient metallic phase is a highly orthorhombically strained rutile metallic phase, an interpretation that is in contrast to those based on spatially averaged probes. Our results demonstrate the critical importance of spatially and spectrally resolved measurements for understanding and interpreting the transient phases of quantum materials.
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Dec 2022
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I06-Nanoscience (XPEEM)
I10-Beamline for Advanced Dichroism - scattering
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Abstract: B2-ordered FeRh undergoes a first-order metamagnetic transition from an antiferromagnet (AF) to a ferromagnet (FM) upon heating. Thin films of B2-ordered FeRh are grown using DC magnetron sputtering and characterized for their behaviour at GHz frequencies and their dynamic behaviour over hour timescales. Ferromagnetic resonance investigations reveal a change in the spectroscopic splitting factor, g, through the range of the transition probed here. By introducing a model that describes the development of the two magnetic phases through the transition, this change in g is shown to be consistent with the development of an exchange coupling across the magnetic phase boundary that induces a non-zero magnetic moment in the AF phase as the result of a thickness dependent phase transition in the AF layer. The influence of such a phase transition is also seen in the extracted value of the Gilbert damping parameter in this experiment. Spin-wave resonance measurements are then performed to try and conclusively measure the exchange coupling between the two magnetic states in FeRh. Measuring the exchange stiffness through the transition reveals that the AF phase has a non-zero exchange energy that varies through the measurement range probed here. The behaviour of the exchange stiffness in the AF layer is attributed to a combination of both the onset of the exchange coupling and the presence of evanescent spin-waves, both of which are consequences of the thickness dependent phase transition in the AF layer. It was then shown that the structure of both magnetic phases could be measured directly with X-Ray Magnetic Dichroism using both linearly and circularly polarized light. The objects measured in these experiments are then characterized for their dynamic properties using X-Ray Photon Correlation Spectroscopy. These studies reveal reveal that the dynamic behaviour of the system is dependent on the type of magnetic dichroism used to probe it. This study also shows it is possible use x-ray magnetic linear dichroism to directly measure the structural and dynamic behaviour of AF materials.
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Sep 2019
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I06-Nanoscience (XPEEM)
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Open Access
Abstract: Accurate evaluation of polarization states of the radiation is necessary for polarization-sensitive studies, which requires polarization optical elements, such as polarizer, analyzer, and phase retarder. In extreme ultraviolet (EUV) and soft X-ray region, the closeness of the real part of the refractive index to unity, coupled with high absorption, makes the realization of polarizers such as birefringence and dichroic polarizers impossible. Periodical multilayers are commonly used in polarization study working at the quasi-Brewster angle. To expand narrow spectral bandwidths of periodic multilayers, aperiodic and lateral gradual multilayer polarizers including reflective analyzers and transmission phase retarders are utilized. In this chapter, we demonstrate a series of periodic, aperiodic, and lateral gradual broadband multilayer polarizers with the material combinations of Mo/Si, Mo/Y, Mo/B4C, Cr/C, Cr/Sc, Cr/Ti, Cr/V, WSi2/Si, W/B4C, etc. Different multilayer polarizers correspond to different energy ranges, covering 50–1000 eV totally, including “water window” and the L absorption edges of Fe, Co, and Ni. Polarization measurements are performed at BESSY II, Diamond Light Source, National Synchrotron Radiation Laboratory in Hefei and Beijing Synchrotron Radiation Facility. Some of the polarizers we have developed are applied to the polarization measurements of BESSY II UE56/1-PGM and Beamline 3W1B of Beijing Synchrotron Radiation Facility.
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Nov 2017
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I06-Nanoscience (XPEEM)
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Elisabeth M.
Bothschafter
,
Elsa
Abreu
,
Laurenz
Rettig
,
Teresa
Kubacka
,
Sergii
Parchenko
,
Michael
Porer
,
Christian
Dornes
,
Yoav William
Windsor
,
Mahesh
Ramakrishnan
,
Aurora
Alberca
,
Sebastian
Manz
,
Jonathan
Saari
,
Seyed M.
Koohpayeh
,
Manfred
Fiebig
,
Thomas
Forrest
,
Philipp
Werner
,
Sarnjeet S.
Dhesi
,
Steven L.
Johnson
,
Urs
Staub
Diamond Proposal Number(s):
[13355, 13926]
Abstract: We investigate the demagnetization dynamics of the cycloidal and sinusoidal phases of multiferroic TbMnO3 by means of time-resolved resonant soft x-ray diffraction following excitation by an optical pump. The use of orthogonal linear x-ray polarizations provides information on the contribution from the different magnetic moment directions, which can be interpreted as signatures from multiferroic cycloidal spin order and sinusoidal spin order. Tracking these signatures in the time domain enables us to identify the transient magnetic phase created by intense photoexcitation of the electrons and subsequent heating of the spin system on a picosecond time scale. The transient phase is shown to exhibit mostly spin density wave character, as in the adiabatic case, while nevertheless retaining the wave vector of the cycloidal long-range order. Two different pump photon energies, 1.55 and 3.1 eV, lead to population of the conduction band predominantly via intersite d−d or intrasite p−d transitions, respectively. We find that the nature of the optical excitation does not play an important role in determining the dynamics of magnetic order melting. Further, we observe that the orbital reconstruction, which is induced by the spin ordering, disappears on a time scale comparable to that of the cycloidal order, attesting to a direct coupling between magnetic order and orbital reconstruction. Our observations are discussed in the context of recent theoretical models of demagnetization dynamics in strongly correlated systems, revealing the potential of this type of measurement as a benchmark for such theoretical studies.
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Nov 2017
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I06-Nanoscience (XPEEM)
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Diamond Proposal Number(s):
[9158, 10430]
Abstract: Control of electronic and structural ordering in correlated materials on the ultrafast timescale with light is a new and emerging approach to disentangle the complex interplay of the charge, spin, orbital and structural degree of freedom. In this paper we present an overview of how orbital order and orbital domains can be controlled by near IR and THz radiation in the layered manganite La0.5Sr1.5MnO4. We show how near-IR pumping can efficiently and rapidly melt orbital ordering. However, the nanoscale domain structure recovers unchanged demonstrating the importance of structural defects for the orbital domain formation. On the contrary, we show that pulsed THz fields can be used to effectively orientate the domains. In this case the alignment depends on the in-plane electric field polarisation and is induced by an energy penalty that arises from THz field induced hopping of the localised charges.
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Dec 2016
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I06-Nanoscience (XPEEM)
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V.
Khanna
,
R.
Mankowsky
,
M.
Petrich
,
H.
Bromberger
,
S.
Cavill
,
E.
Möhr-Vorobeva
,
D.
Nicoletti
,
Y.
Laplace
,
G. D.
Gu
,
J. P.
Hill
,
M.
Foerst
,
A.
Cavalleri
,
S.
Dhesi
Diamond Proposal Number(s):
[7497, 7942, 8207]
Abstract: We show that disruption of charge-density-wave (stripe) order by charge transfer excitation, enhances the superconducting phase rigidity in La1.885Ba0.115CuO4. Time-resolved resonant soft x-ray diffraction demonstrates that charge order melting is prompt following near-infrared photoexcitation whereas the crystal structure remains intact for moderate fluences. THz time-domain spectroscopy reveals that, for the first 2 ps following photoexcitation, a new Josephson plasma resonance edge, at higher frequency with respect to the equilibrium edge, is induced indicating enhanced superconducting interlayer coupling. The fluence dependence of the charge-order melting and the enhanced superconducting interlayer coupling are correlated with a saturation limit of ∼0.5mJ/cm2. Using a combination of x-ray and optical spectroscopies we establish a hierarchy of timescales between enhanced superconductivity, melting of charge order, and rearrangement of the crystal structure.
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Jun 2016
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I06-Nanoscience (XPEEM)
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Michael
Först
,
Andrea
Caviglia
,
Raoul
Scherwitzl
,
Pavlo
Zubko
,
Hubertus
Bromberger
,
Roman
Mankowsky
,
Stuart
Wilkins
,
Yi De
Chuang
,
Wei-Sheng
Lee
,
William F.
Schlotter
,
Joshua J.
Turner
,
Georgi L.
Dakovski
,
Michael
Minitti
,
Joe
Robinson
,
Jean Marc
Triscone
,
Sarnjeet
Dhesi
,
Andrea
Cavalleri
Diamond Proposal Number(s):
[7285]
Abstract: We use femtosecond Resonant Soft X-ray Diffraction to observe heterogeneous melting of antiferromagnetic order in an epitaxially grown NdNiO3 film. Cross-interface coupling launches a propagating phase front following direct lattice excitation of the LaAlO3 substrate.
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Jan 2015
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