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78 items found (0 items not approved), displaying 1 to 10.[First/Prev] 1, 2, 3, 4, 5, 6, 7, 8 [Next/Last]

Instruments / Technical Area	Publication Details	Published
I13-2-Diamond Manchester Imaging	Femtosecond laser preparation of resin embedded samples for correlative microscopy workflows in life sciences Carles Bosch , Joerg Lindenau , Alexandra Pacureanu , Christopher J. Peddie , Marta Majkut , Andrew C. Douglas , Raffaella Carzaniga , Alexander Rack , Lucy Collinson , Andreas T. Schaefer , Heiko Stegmann Applied Physics Letters 122 DOI: 10.1063/5.0142405 Diamond Proposal Number(s): [20274] Open Access Show Abstract ▼ Abstract: Correlative multimodal imaging is a useful approach to investigate complex structural relations in life sciences across multiple scales. For these experiments, sample preparation workflows that are compatible with multiple imaging techniques must be established. In one such implementation, a fluorescently labeled region of interest in a biological soft tissue sample can be imaged with light microscopy before staining the specimen with heavy metals, enabling follow-up higher resolution structural imaging at the targeted location, bringing context where it is required. Alternatively, or in addition to fluorescence imaging, other microscopy methods, such as synchrotron x-ray computed tomography with propagation-based phase contrast or serial blockface scanning electron microscopy, might also be applied. When combining imaging techniques across scales, it is common that a volumetric region of interest (ROI) needs to be carved from the total sample volume before high resolution imaging with a subsequent technique can be performed. In these situations, the overall success of the correlative workflow depends on the precise targeting of the ROI and the trimming of the sample down to a suitable dimension and geometry for downstream imaging. Here, we showcase the utility of a femtosecond laser (fs laser) device to prepare microscopic samples (1) of an optimized geometry for synchrotron x-ray tomography as well as (2) for volume electron microscopy applications and compatible with correlative multimodal imaging workflows that link both imaging modalities.	Apr 2023
I09-Surface and Interface Structural Analysis	The electronic structure of β-TeO 2 as wide bandgap p-type oxide semiconductor Jueli Shi , Ziqian Sheng , Ling Zhu , Xiangyu Xu , Yun Gao , Dingliang Tang , Kelvin H. L. Zhang Applied Physics Letters 122 DOI: 10.1063/5.0142734 Diamond Proposal Number(s): [24219, 31681] Show Abstract ▼ Abstract: Wide bandgap oxide semiconductors have gained significant attention in the fields from flat panel displays to solar cells, but their uses have been limited by the lack of high mobility p-type oxide semiconductors. Recently, β-phase TeO2 has been identified as a promising p-type oxide semiconductor with exceptional device performance. In this Letter, we report on the electronic structure of β-TeO2 studied by a combination of high-resolution x-ray spectroscopy and hybrid density functional theory calculations. The bulk bandgap of β-TeO2 is determined to be 3.7 eV. Direct comparisons between experimental and computational results demonstrate that the top of a valence band (VB) of β-TeO2 is composed of the hybridized Te 5s, Te 5p, and O 2p states, whereas a conduction band (CB) is dominated by unoccupied Te 5p states. The hybridization between spatially dispersive Te 5s2 states and O 2p orbitals helps us to alleviate the strong localization in the VB, leading to small hole effective mass and high hole mobility in β-TeO2. The Te 5p states provide stabilizing effect to the hybridized Te 5s-O 2p states, which is enabled by structural distortions of a β-TeO2 lattice. The multiple advantages of large bandgap, high hole mobility, two-dimensional structure, and excellent stability make β-TeO2 a highly competitive material for next-generation opto-electronic devices.	Mar 2023
I09-Surface and Interface Structural Analysis	Using polycyclic aromatic hydrocarbons for graphene growth on Cu(111) under ultra-high vacuum Benedikt P. Klein , Matthew A. Stoodley , Matthew Edmondson , Luke A. Rochford , Marc Walker , Lars Sattler , Sebastian Weber , Gerhard Hilt , Leon B. S. Williams , Tien-Lin Lee , Alex Saywell , Reinhard J. Maurer , David A. Duncan Applied Physics Letters 121 DOI: 10.1063/5.0122914 Diamond Proposal Number(s): [25379] Open Access Show Abstract ▼ Abstract: Ultra-high vacuum deposition of the polycyclic aromatic hydrocarbons azupyrene and pyrene onto a Cu(111) surface held at a temperature of 1000 K is herein shown to result in the formation of graphene. The presence of graphene was proven using scanning tunneling microscopy, x-ray photoelectron spectroscopy, angle-resolved photoemission spectroscopy, Raman spectroscopy, and low energy electron diffraction. The precursors, azupyrene and pyrene, are comparatively large aromatic molecules in contrast to more commonly employed precursors like methane or ethylene. While the formation of the hexagonal graphene lattice could naively be expected when pyrene is used as a precursor, the situation is more complex for azupyrene. In this case, the non-alternant topology of azupyrene with only 5- and 7-membered rings must be altered to form the observed hexagonal graphene lattice. Such a rearrangement, converting a non-alternant topology into an alternant one, is in line with previous reports describing similar topological alterations, including the isomerization of molecular azupyrene to pyrene. The thermal synthesis route to graphene, presented here, is achievable at comparatively low temperatures and under ultra-high vacuum conditions, which may enable further investigations of the growth process in a strictly controlled and clean environment that is not accessible with traditional precursors.	Nov 2022
I11-High Resolution Powder Diffraction	Layered structure transformations and exfoliation of h-BN during thermal cycling Zhengyu Yan , Amor Abdelkader , Wajira Mirihanage Applied Physics Letters 121 DOI: 10.1063/5.0119953 Diamond Proposal Number(s): [14099] Show Abstract ▼ Abstract: Understanding structural transformation of hexagonal boron nitride (h-BN) at elevated temperatures is critical to obtain 2D-h-BN through thermal exfoliation. Therefore, in situ x-ray diffraction data are collected from h-BN powders while subjecting them to a thermal cycle. The potential to define the structure order during temperature variations is revealed by using an index (I3D). It was revealed that no direct correlation with the degree of exfoliation of layered structure and the structural order change appeared during thermal cycling. Furthermore, particle size dependence of the structure order under elevated temperature is also mapped.	Oct 2022
I14-Hard X-ray Nanoprobe	Scanning x-ray microscopy: A sub-100 nm probe toward strain and composition in seeded horizontal Ge(110) nanowires Michael Hanke , Carsten Richter , Felix Lange , Anna Reis , Julia Parker , Torsten Boeck Applied Physics Letters 120 DOI: 10.1063/5.0085788 Diamond Proposal Number(s): [22484] Open Access Show Abstract ▼ Abstract: We have spatially investigated lattice spacing, twist, and bending in individual laterally (110)-oriented Ge nanowires (NWs) on pre-patterned Si(001) substrates. A combination of synchrotron-based scanning x-ray diffraction microscopy with an x-ray focus size of 50 nm and numerical finite element calculations on the elastic strain reveals a three-dimensional relaxation scenario, which becomes particularly complex next to NW nucleation points. Despite a lattice mismatch of 4.2%, lattice compliance is preserved, since strain can effectively be released close to the seeding window. Areas in the NWs other than that appear fully relaxed. The resulting NW twist, i.e., lattice rotations around the growth axis, amounts to less than 0.1°.	Mar 2022
	Substrate dependent reduction of Gilbert damping in annealed Heusler alloy thin films grown on group IV semiconductors C. J. Love , B. Kuerbanjiang , A. Kerrigan , S. Yamada , K. Hamaya , G. Van Der Laan , V. K. Lazarov , S. A. Cavill Applied Physics Letters 119 DOI: 10.1063/5.0060213 Open Access Show Abstract ▼ Abstract: A structural and FMR study is presented for epitaxial thin films of the Heusler alloy Co2FeAl0.5Si0.5 (CFAS) grown on Ge(111) and Si(111) substrates. All films, as-grown and post-annealed, show B2 ordering; full chemical order (L21) is not obtained over the range of anneal temperatures used in this study. As-grown films show a lower Gilbert damping constant, α, when grown on a Si(111) substrate compared to Ge(111). Annealing the films to 450 °C significantly reduces α for CFAS on Ge while increasing α for CFAS on Si. This is related to a substrate dependent competition between improvements in lattice structure and increased interfacial intermixing as a function of anneal temperature. The optimal annealing temperature to minimize α is found to differ by ∼100 K between the two substrates. Above an anneal temperature of 500 °C, films grown on both substrates have increased coercivity, decreased saturation magnetization, and show characteristic two-magnon scattering features.	Oct 2021
I10-Beamline for Advanced Dichroism	Probing the atomic-scale ferromagnetism in van der Waals magnet CrSiTe3 Wei Niu , Xiaoqian Zhang , Wei Wang , Jiabao Sun , Yongbing Xu , Liang He , Wenqing Liu , Yong Pu Applied Physics Letters 119 DOI: 10.1063/5.0069885 Diamond Proposal Number(s): [16538] Open Access Show Abstract ▼ 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.	Oct 2021
B16-Test Beamline Optics	Aberration characterization of x-ray optics using multi-modal ptychography and a partially coherent source Thomas E. J. Moxham , David Laundy , Vishal Dhamgaye , Oliver J. L. Fox , Kawal Sawhney , Alexander M. Korsunsky Applied Physics Letters 118 DOI: 10.1063/5.0041341 Show Abstract ▼ Abstract: Ptychography is a scanning coherent diffraction imaging technique that provides high-resolution imaging and complete spatial information of the complex probe and object transmission function. The wavefront error caused by aberrated optics has previously been recovered using ptychography when a highly coherent source is used, but has not been demonstrated with partial coherence due to the multi-modal probe required. Here, we demonstrate that partial coherence can be accounted for in ptychographic reconstructions using the multi-modal approach and assuming that decoherence arises from either the probe or the object. This equivalence recovers coherent (or single state) reconstructions of both the probe and the object even in the presence of partial coherence. We demonstrate this experimentally by using hard x-ray ptychography with a partially coherent source to image a Siemens star test object and to also recover the wavefront error from an aberrated beryllium compound refractive lens. The source properties and resolving capabilities are analyzed, and the wavefront error results are compared with another at-wavelength metrology technique. Our work demonstrates the capability of ptychography to provide high-resolution imaging and optics characterization even in the presence of partial coherence.	Mar 2021
I06-Nanoscience	An insulating doped antiferromagnet with low magnetic symmetry as a room temperature spin conduit Andrew Ross , Romain Lebrun , Lorenzo Baldrati , Akashdeep Kamra , Olena Gomonay , Shilei Ding , Felix Schreiber , Dirk Backes , Francesco Maccherozzi , Daniel A. Grave , Avner Rothschild , Jairo Sinova , Mathias Klaui Applied Physics Letters 117 DOI: 10.1063/5.0032940 Diamond Proposal Number(s): [23819] Show Abstract ▼ Abstract: We report room-temperature long-distance spin transport of magnons in antiferromagnetic thin-film hematite doped with Zn. The additional dopants significantly alter the magnetic anisotropies, resulting in a complex equilibrium spin structure that is capable of efficiently transporting spin angular momentum at room temperature without the need for a well-defined, pure easy-axis or easy-plane anisotropy. We find intrinsic magnon spin-diffusion lengths of up to 1.5 μm, and magnetic domain governed decay lengths of 175 nm for the low-frequency magnons, through electrical transport measurements demonstrating that the introduction of nonmagnetic dopants does not strongly reduce the transport length scale, showing that the magnetic damping of hematite is not significantly increased. We observe a complex field dependence of the nonlocal signal independent of the magnetic state visible, in the local magnetoresistance and direct magnetic imaging of the antiferromagnetic domain structure. We explain our results in terms of a varying and applied field-dependent ellipticity of the magnon modes reaching the detector electrode allowing us to tune the spin transport.	Dec 2020
I10-Beamline for Advanced Dichroism	Direct observation of ferrimagnetic ordering in inverse Heusler alloy Mn 2 CoAl Zhendong Chen , Wenqing Liu , Peng Chen , Xuezhong Ruan , Jiabao Sun , Ruobai Liu , Cunxu Gao , Jun Du , Bo Liu , Hao Meng , Rong Zhang , Yongbing Xu Applied Physics Letters 117 DOI: 10.1063/5.0013656 Diamond Proposal Number(s): [22532] Show Abstract ▼ Abstract: Compensated ferrimagnetic Heusler compounds with high spin polarization and a low net magnetic moment are strategically important materials for spin-logic and further energy-efficient spintronic applications. However, the element-resolved magnetic ordering of these compensated ferrimagnets remains an open issue. Here, we report a direct observation of the spin and orbital moments of the B2 phase Mn2CoAl thin film using the synchrotron-based x-ray magnetic circular dichroism technique. An ferrimagnetic ordering between Mn and Co elements and a compensated-ferrimagnet-like small net magnetic moment of only 0.34 μB/f.u. were observed unambiguously in B2 Mn2CoAl. Antiparallel coupling between Mn and Co is attributed to the mixture of the Mn(B) and Al occupation in the B2 phase Mn2CoAl lattice. This work demonstrates great potential of the compensated ferrimagnetic half-metallic inverse Heusler compounds Mn2CoAl for spintronic applications.	Jul 2020

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