Search Results

You searched for all publications:

with publication states 'Published (Approved)'
published in journal 'Physical Review Letters'

Search Again...

These results only include publications that have been reviewed and processed by Diamond Light Source. To also view papers that have not yet been processed click here.

You can use the folder icon under Actions to collate papers as required. You can then click on View Folder in the left-hand navigation to review and/or download your folder.

Exact matches
Related results

141 items found (0 items not approved), displaying 71 to 80.[First/Prev] 4, 5, 6, 7, 8, 9, 10, 11 [Next/Last]

Instruments / Technical Area	Publication Details	Published
I06-Nanoscience (XPEEM)	Imaging current-induced switching of antiferromagnetic domains in CuMnAs M. J. Grzybowski , P. Wadley , K. W. Edmonds , R. Beardsley , V. Hills , R. P. Campion , B. L. Gallagher , J. S. Chauhan , V. Novak , T. Jungwirth , F. Maccherozzi , S. S. Dhesi Physical Review Letters 118 DOI: 10.1103/PhysRevLett.118.057701 Diamond Proposal Number(s): [12504] Show Abstract ▼ Abstract: The magnetic order in antiferromagnetic materials is hard to control with external magnetic fields. Using x-ray magnetic linear dichroism microscopy, we show that staggered effective fields generated by electrical current can induce modification of the antiferromagnetic domain structure in microdevices fabricated from a tetragonal CuMnAs thin film. A clear correlation between the average domain orientation and the anisotropy of the electrical resistance is demonstrated, with both showing reproducible switching in response to orthogonally applied current pulses. However, the behavior is inhomogeneous at the submicron level, highlighting the complex nature of the switching process in multidomain antiferromagnetic films.	Feb 2017
I15-Extreme Conditions	Ultrafast x-ray diffraction studies of the phase transitions and equation of state of scandium shock compressed to 82 GPa R. Briggs , M. G. Gorman , A. l. Coleman , R. s. Mcwilliams , E. e. Mcbride , D. Mcgonegle , J. s. Wark , L. Peacock , S. Rothman , S. g. Macleod , C. a. Bolme , A. e. Gleason , G. w. Collins , J. h. Eggert , D. e. Fratanduono , R. f. Smith , E. Galtier , E. Granados , H. j. Lee , B. Nagler , I. Nam , Z. Xing , M. I. Mcmahon Physical Review Letters 118 DOI: 10.1103/PhysRevLett.118.025501 Diamond Proposal Number(s): [13620] Show Abstract ▼ Abstract: Using x-ray diffraction at the Linac Coherent Light Source x-ray free-electron laser, we have determined simultaneously and self-consistently the phase transitions and equation of state (EOS) of the lightest transition metal, scandium, under shock compression. On compression scandium undergoes a structural phase transition between 32 and 35 GPa to the same bcc structure seen at high temperatures at ambient pressures, and then a further transition at 46 GPa to the incommensurate host-guest polymorph found above 21 GPa in static compression at room temperature. Shock melting of the host-guest phase is observed between 53 and 72 GPa with the disappearance of Bragg scattering and the growth of a broad asymmetric diffraction peak from the high-density liquid.	Jan 2017
I16-Materials and Magnetism	Multiple supersonic phase fronts launched at a complex-oxide heterointerface M. Forst , K. R. Beyerlein , R. Mankowsky , W. Hu , G. Mattoni , S. Catalano , M. Gibert , O. Yefanov , J. N. Clark , A. Frano , J. M. Glownia , M. Chollet , H. Lemke , B. Moser , S. P. Collins , S. S. Dhesi , A. D. Caviglia , J.-M. Triscone , A. Cavalleri Physical Review Letters 118 DOI: 10.1103/PhysRevLett.118.027401 Diamond Proposal Number(s): [11118] Show Abstract ▼ Abstract: Selective optical excitation of a substrate lattice can drive phase changes across heterointerfaces. This phenomenon is a nonequilibrium analogue of static strain control in heterostructures and may lead to new applications in optically controlled phase change devices. Here, we make use of time-resolved nonresonant and resonant x-ray diffraction to clarify the underlying physics and to separate different microscopic degrees of freedom in space and time. We measure the dynamics of the lattice and that of the charge disproportionation in NdNiO3, when an insulator-metal transition is driven by coherent lattice distortions in the LaAlO3 substrate. We find that charge redistribution propagates at supersonic speeds from the interface into the NdNiO3 film, followed by a sonic lattice wave. When combined with measurements of magnetic disordering and of the metal-insulator transition, these results establish a hierarchy of events for ultrafast control at complex-oxide heterointerfaces.	Jan 2017
	Generation and evolution of spin-, valley-, and layer-polarized excited carriers in inversion-symmetric R. Bertoni , C. W. Nicholson , L. Waldecker , H. Hübener , C. Monney , U. De Giovannini , M. Puppin , M. Hoesch , E. Springate , R. T. Chapman , C. Cacho , M. Wolf , A. Rubio , R. Ernstorfer Physical Review Letters 117 DOI: 10.1103/PhysRevLett.117.277201 Show Abstract ▼ Abstract: We report the spin-selective optical excitation of carriers in inversion-symmetric bulk samples of the transition metal dichalcogenide (TMDC) WSe 2 . Employing time- and angle-resolved photoelectron spectroscopy (trARPES) and complementary time-dependent density functional theory (TDDFT), we observe spin-, valley-, and layer-polarized excited state populations upon excitation with circularly polarized pump pulses, followed by ultrafast (<100 fs ) scattering of carriers towards the global minimum of the conduction band. TDDFT reveals the character of the conduction band, into which electrons are initially excited, to be two-dimensional and localized within individual layers, whereas at the minimum of the conduction band, states have a three-dimensional character, facilitating interlayer charge transfer. These results establish the optical control of coupled spin-, valley-, and layer-polarized states in centrosymmetric materials with locally broken symmetries and suggest the suitability of TMDC multilayer and heterostructure materials for valleytronic and spintronic device concepts.	Dec 2016
I05-ARPES	Highly anisotropic and twofold symmetric superconducting gap in nematically ordered FeSe0.93S0.07 H. C. Xu , X. H. Niu , D. F. Xu , J. Jiang , Q. Yao , Q. Y. Chen , Q. Song , M. Abdel-Hafiez , D. A. Chareev , A. N. Vasiliev , Q. S. Wang , H. l. Wo , J. Zhao , R. Peng , D. l. Feng Physical Review Letters 117 DOI: 10.1103/PhysRevLett.117.157003 Diamond Proposal Number(s): [11914, 12849] Show Abstract ▼ Abstract: FeSe exhibits a novel ground state in which superconductivity coexists with a nematic order in the absence of any long-range magnetic order. Here, we report on an angle-resolved photoemission study on the superconducting gap structure in the nematic state of FeSe0.93S0.07, without the complications caused by Fermi surface reconstruction induced by magnetic order. We find that the superconducting gap shows a pronounced twofold anisotropy around the elliptical hole pocket near Z (0, 0, π), with gap minima at the end points of its major axis, while no detectable gap is observed around Γ (0, 0, 0) and the zone corner (π, π, kz). The large anisotropy and nodal gap distribution demonstrate the substantial effects of the nematicity on the superconductivity and thus put strong constraints on current theories.	Oct 2016
I06-Nanoscience (XPEEM) I16-Materials and Magnetism	Coherent magnetoelastic domains in multiferroic BiFeO3 films N. Waterfield Price , R. D. Johnson , W. Saenrang , F. Maccherozzi , S. S. Dhesi , A. Bombardi , F. P. Chmiel , C-B. Eom , P. Radaelli Physical Review Letters 117 DOI: 10.1103/PhysRevLett.117.177601 Diamond Proposal Number(s): [10201] Show Abstract ▼ Abstract: The physical properties of epitaxial films can fundamentally differ from those of bulk single crystals even above the critical thickness. By a combination of nonresonant x-ray magnetic scattering, neutron diffraction and vector-mapped x-ray magnetic linear dichroism photoemission electron microscopy, we show that epitaxial (111)-BiFeO3 films support submicron antiferromagnetic domains, which are magnetoelastically coupled to a coherent crystallographic monoclinic twin structure. This unique texture, which is absent in bulk single crystals, should enable control of magnetism in BiFeO3 film devices via epitaxial strain.	Oct 2016
I06-Nanoscience (XPEEM)	Long spin diffusion length in few-layer graphene flakes W. Yan , L. C. Phillips , M. Barbone , S. J. Hämäläinen , A. Lombardo , M. Ghidini , Xavier Moya , F. Maccherozzi , S. Van Dijken , S. S. Dhesi , A. C. Ferrari , N. D. Mathur Physical Review Letters 117 DOI: 10.1103/PhysRevLett.117.147201 Diamond Proposal Number(s): [1773, 6249, 8325] Show Abstract ▼ Abstract: We report a spin valve with a few-layer graphene flake bridging highly spin-polarized La0.67Sr0.33MnO3 electrodes, whose surfaces are kept clean during lithographic definition. Sharp magnetic switching is verified using photoemission electron microscopy with x-ray magnetic circular dichroism contrast. A naturally occurring high interfacial resistance ∼12 MΩ facilitates spin injection, and a large resistive switching (0.8 MΩ at 10 K) implies a 70–130 μm spin diffusion length that exceeds previous values obtained with sharp-switching electrodes.	Sep 2016
I22-Small angle scattering & Diffraction	Neurofilaments function as shock absorbers: compression response arising from disordered proteins Micha Kornreich , Eti Malka-Gibor , Ben Zuker , Adi Laser-Azogui , Roy Beck Physical Review Letters 117 DOI: 10.1103/PhysRevLett.117.148101 Diamond Proposal Number(s): [11549] Show Abstract ▼ Abstract: What can cells gain by using disordered, rather than folded, proteins in the architecture of their skeleton? Disordered proteins take multiple coexisting conformations, and often contain segments which act as random-walk-shaped polymers. Using x-ray scattering we measure the compression response of disordered protein hydrogels, which are the main stress-responsive component of neuron cells. We find that at high compression their mechanics are dominated by gaslike steric and ionic repulsions. At low compression, specific attractive interactions dominate. This is demonstrated by the considerable hydrogel expansion induced by the truncation of critical short protein segments. Accordingly, the floppy disordered proteins form a weakly cross-bridged hydrogel, and act as shock absorbers that sustain large deformations without failure.	Sep 2016
	Direct detection of pure ac spin current by X-ray pump-probe measurements J. Li , L. R. Shelford , P. Shafer , A. Tan , J. X. Deng , P. S. Keatley , C. Hwang , E. Arenholz , G. Van Der Laan , R. J. Hicken , Z. q. Qiu Physical Review Letters 117 DOI: 10.1103/PhysRevLett.117.076602 Show Abstract ▼ Abstract: Despite recent progress in spin-current research, the detection of spin current has mostly remained indirect. By synchronizing a microwave waveform with synchrotron x-ray pulses, we use the ferromagnetic resonance of the Py (Ni 81 Fe 19 ) layer in a Py/Cu/Cu 75 Mn 25 /Cu/Co multilayer to pump a pure ac spin current into the Cu 75 Mn 25 and Co layers, and then directly probe the spin current within the Cu 75 Mn 25 layer and the spin dynamics of the Co layer by x-ray magnetic circular dichroism. This element-resolved pump-probe measurement unambiguously identifies the ac spin current in the Cu 75 Mn 25 layer.	Aug 2016
I09-Surface and Interface Structural Analysis	Modifying the surface of a Rashba-split Pb-Ag alloy using tailored metal-organic bonds Benjamin Stadtmueller , Johannes Seidel , Norman Haag , Lisa Grad , Christian Tusche , Gerben Van Straaten , Markus Franke , Jürgen Kirschner , Christian Kumpf , Mirko Cinchetti , Martin Aeschlimann Physical Review Letters 117, 096805 DOI: 10.1103/PhysRevLett.117.096805 Diamond Proposal Number(s): [10370, 11915] Show Abstract ▼ Abstract: Hybridization-related modifications of the first metal layer of a metal-organic interface are difficult to access experimentally and have been largely neglected so far. Here, we study the influence of specific chemical bonds (as formed by the organic molecules CuPc and PTCDA) on a Pb-Ag surface alloy.We find that delocalized van der Waals or weak chemical π-type bonds are not strong enough to alter the alloy, while localized σ-type bonds lead to a vertical displacement of the Pb surface atoms and to changes in the alloy’s surface band structure. Our results provide an exciting platform for tuning the Rashba-type spin texture of surface alloys using organic molecules.	Aug 2016

Publications Database

Search Results

You searched for all publications:

Search Again...

Subject Areas (check all that apply) select all

Instruments used to collect data (check all that apply) select all

Collaborations involved (check all that apply) select all

Diamond Offline Facilities used

Relevant Technical Areas (check all that apply) select all

Menu for Anonymous User