Scholars@Duke
Divine P Kumah

Divine P Kumah

Associate Professor of Physics
Physics
divine.kumah@duke.edu
Box 90305, Durham, NC 27708
120 Science Dr., Physics Bldg. Room 077, Durham, NC 27708

Selected Publications

The Role of Interfacial Interactions and Oxygen Vacancies in Tuning Magnetic Anisotropy in LaCrO3/LaMnO3 Heterostructures

Journal Article Advanced Materials Interfaces · September 3, 2024 The interplay of lattice, electronic, and spin degrees of freedom at epitaxial complex oxide interfaces provides a route to tune their magnetic ground states. Unraveling the competing contributions is critical for tuning their functional properties. The re ... Full text Cite

Tuning the interlayer coupling in La0.7Sr0.3Mn0.95Ru0.05 O3/LaNiO3 multilayers with perpendicular magnetic anisotropy

Journal Article Physical Review Materials · September 1, 2024 In ferromagnetic oxide epitaxial multilayers, magnetic properties and interlayer coupling are determined by a variety of factors. Beyond the contribution of interlayer exchange coupling, strain and interfacial effects, such as structural reconstructions or ... Full text Cite

In Situ Scattering Studies of Superconducting Vacancy‐Ordered Monoclinic TiO Thin Films

Journal Article Advanced Physics Research · March 2024 AbstractThe structural and transport properties of vacancy‐ordered monoclinic superconducting titanium oxide (TiO) thin films grown by molecular beam epitaxy are investigated. The evolution of the crystal structure during g ... Full text Open Access Cite

A different facet to materials design

Journal Article Nature Physics · January 1, 2024 Complex oxides have competing phases with different spin, electronic and orbital order. Now it has been shown that growing thin films on different facets of a low-symmetry substrate can be used to control the phase of the ground state. ... Full text Cite

Thermal Conductivity of Barium Bismuthate at Low Temperatures

Journal Article New Physics: Sae Mulli · December 1, 2023 The perovskite BaBiO3 crystallizes in a cubic structure and undergoes structural transitions toward lower symmetry phases upon cooling. The two low-temperature monoclinic phases are insulating, and the origin of this unexpected non-metallic character has b ... Full text Cite

Enhanced Critical Field of Superconductivity at an Oxide Interface.

Journal Article Nano letters · August 2023 The nature of superconductivity and its interplay with strong spin-orbit coupling at the KTaO3(111) interfaces remain a subject of debate. To address this problem, we grew epitaxial LaMnO3/KTaO3(111) heterostructures. We sh ... Full text Cite

Thickness-Dependent Thermal Conductivity and Phonon Mean Free Path Distribution in Single-Crystalline Barium Titanate.

Journal Article Advanced science (Weinheim, Baden-Wurttemberg, Germany) · July 2023 Nanosized perovskite ferroelectrics are widely employed in several electromechanical, photonics, and thermoelectric applications. Scaling of ferroelectric materials entails a severe reduction in the lattice (phonon) thermal conductivity, particularly at su ... Full text Cite

Ferroelectric Domain Wall Engineering Enables Thermal Modulation in PMN-PT Single Crystals.

Journal Article Advanced materials (Deerfield Beach, Fla.) · June 2023 Acting like thermal resistances, ferroelectric domain walls can be manipulated to realize dynamic modulation of thermal conductivity (k), which is essential for developing novel phononic circuits. Despite the interest, little attention has been paid to ach ... Full text Cite

The Role of Carbon Content: A Comparison of the Nickel Particle Size and Magnetic Property of Nickel/Polysiloxane-Derived Silicon Oxycarbide

Journal Article Advanced Engineering Materials · May 1, 2023 A facile and novel processable method to synthesize the Ni nanoparticles (Ni NPs) by tailoring their size in the matrix of the silicon oxycarbide (SiOC) ceramic system is reported. This method is based on polymer-derived ceramics (PDCs), instead of the con ... Full text Cite

Anisotropic superconductivity at KTaO3(111) interfaces.

Journal Article Science advances · February 2023 A two-dimensional, anisotropic superconductivity was recently found at the KTaO3(111) interfaces. The nature of the anisotropic superconducting transition remains a subject of debate. To investigate the origins of the observed behavior, we grew ... Full text Cite

Oxygen Vacancy-Induced Anomalous Hall Effect in a Nominally Non-magnetic Oxide

Journal Article Journal of Electronic Materials · December 1, 2022 The anomalous Hall effect, a hallmark of broken time-reversal symmetry and spin–orbit coupling, is frequently observed in magnetically polarized systems. However, its realization in nominally non-magnetic systems remains elusive. Here, we report on the obs ... Full text Cite

Superconductivity and Weak Anti-localization at KTaO3 (111) Interfaces

Journal Article Journal of Electronic Materials · November 1, 2022 The intersection of two-dimensional superconductivity and topologically nontrivial states hosts a wide range of quantum phenomena, including Majorana fermions. We report on the observation of two-dimensional superconductivity and weak anti-localization at ... Full text Cite

Superconducting phase of Tix Oy thin films grown by molecular beam epitaxy

Journal Article Physical Review Materials · June 1, 2022 We investigate the complex relationship between the growth conditions and the structural and transport properties of TixOy thin films grown by molecular beam epitaxy. Transport properties ranging from metallicity to superconductivity and insulating states ... Full text Cite

Thickness and temperature dependence of the atomic-scale structure of SrRuO3thin films

Journal Article APL Materials · May 1, 2022 The temperature-dependent layer-resolved structure of 3 to 44 unit cell thick SrRuO3 (SRO) films grown on Nb-doped SrTiO3 substrates is investigated using a combination of high-resolution synchrotron x-ray diffraction and high-resolution electron microscop ... Full text Cite

Effect of buffer termination on intermixing and conductivity in LaTiO3/SrTiO3heterostructures integrated on Si(100)

Journal Article Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films · January 1, 2022 The control of chemical exchange across heterointerfaces formed between ultrathin functional transition-metal oxide layers provides an effective route to manipulate the electronic properties of these systems. By determining the layer-resolved structural pr ... Full text Cite

Two-dimensional electron systems and interfacial coupling in LaCrO3/KTaO3heterostructures

Journal Article Applied Physics Letters · May 10, 2021 The strong interfacial coupling at the 3d-5d transition metal-oxide interfaces has generated excitement due to the possibility of engineering a wide range of quantum phenomena and functionalities. Here, we investigate the electronic interfacial coupling an ... Full text Cite

Interface-driven magnetic anisotropy in relaxed La0.7Sr0.3CrO3/La0.7Sr0.3MnO3heterostructures on MgO

Journal Article Journal of Applied Physics · February 7, 2021 We investigate the structural and magnetic properties of La 0.7 Sr 0.3 CrO 3 (LSCO) / La 0.7 Sr 0.3 MnO 3 (LSMO) heterostructures grown on (001)-oriented MgO by molecular beam epitaxy. Due to the large film-substrate lattice mismatch, strain relaxation is ... Full text Cite

Tuning of spin-orbit coupling in metal-free conjugated polymers by structural conformation

Journal Article Physical Review Materials · August 1, 2020 Manipulating spin-orbit coupling (SOC) is a key achievement for spin-orbitronic applications since SOC determines spin-diffusion lengths and spin-to-charge conversion efficiencies. While in most organic semiconductors SOC is inherently very weak due to bei ... Full text Cite

Epitaxial Oxides on Semiconductors: From Fundamentals to New Devices

Journal Article Advanced Functional Materials · May 1, 2020 Functional oxides are an untapped resource for futuristic devices and functionalities. These functionalities can range from high temperature superconductivity to multiferroicity and novel catalytic schemes. The most prominent route for transforming these i ... Full text Cite

On the redistribution of charge in La0.7Sr0.3CrO3/La0.7Sr0.3MnO3 multilayer thin films

Journal Article AIP Advances · April 1, 2020 The atomic and electronic structures of La0.7Sr0.3MnO3 (LSMO)/La0.7Sr0.3CrO3 (LSCO) multilayer thin films are investigated using aberration corrected scanning transmission electron microscopy (STEM) imaging and spectroscopy. Atomic resolution high angle an ... Full text Cite

Correlating polar distortions and interfacial charge at the polar/non-polar LaCrO3/SrTiO3(001) interface

Journal Article AIP Advances · April 1, 2020 The relationship between the sheet carrier concentration, ns, of LaCrO3(LCO)/SrTiO3(STO) heterostructures and their structural properties has been investigated. Under low oxygen partial pressure, the STO substrate is reduced during growth as evidenced by a ... Full text Cite

Effect of strain on magnetic and orbital ordering of LaSrCrO3/LaSrMnO3 heterostructures

Journal Article Physical Review B · February 1, 2020 We investigate the effect of strain and film thickness on the orbital and magnetic properties of LaSrCrO3(LSCO)/LaSrMnO3 (LSMO) heterostructures using bulk magnetometry, soft X-ray magnetic spectroscopy, first-principles density-functional theory, high-res ... Full text Cite

Exchange bias in La0.7Sr0.3CrO3/La0.7Sr0.3MnO3/La0.7Sr0.3CrO3 heterostructures

Journal Article AIP Advances · January 1, 2020 In the recent past, heterostructures of magnetic oxide thin films have attracted a great deal of research excitement due to very interesting physical properties such as antiferromagnetic interlayer coupling, tunable exchange-bias, interfacial driven magnet ... Full text Cite

Suspended single-crystalline oxide structures on silicon through wet-etch techniques: Effects of oxygen vacancies and dislocations on etch rates

Journal Article Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films · January 1, 2020 Wet-etch techniques to realize suspended microscale structures of single-crystalline SrTiO3 and BaTiO3 grown on Si are explored. The authors examine the effects of oxygen vacancies and dislocations on etch rates. Both oxygen vacancies and dislocations enha ... Full text Cite

Confinement of magnetism in atomically thin La0.7Sr0.3CrO3/La0.7Sr0.3MnO3 heterostructures

Journal Article npj Quantum Materials · December 1, 2019 At crystalline interfaces where a valence-mismatch exists, electronic, and structural interactions may occur to relieve the polar mismatch, leading to the stabilization of non-bulk-like phases. We show that spontaneous reconstructions at polar La0.7Sr0.3Mn ... Full text Cite

Growth-temperature dependence of conductivity at the LaCrO 3 /SrTiO 3 (001) interface

Journal Article Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films · March 1, 2019 The effect of growth conditions and postgrowth treatment on the structural and electronic properties of the polar/nonpolar LaCrO3/SrTiO3 (LCO/STO) interface has been investigated. Under low oxygen partial pressure, oxygen vacancies are formed in the STO su ... Full text Cite

Interfacial structure of SrZrxTi1-xO3 films on Ge

Journal Article Applied Physics Letters · November 12, 2018 The interfacial structure of SrZrxTi1-xO3 films grown on semiconducting Ge substrates is investigated by synchrotron X-ray diffraction and first-principles density functional theory. By systematically tuning the Zr content x, the effects of bonding at the ... Full text Cite

Tuning metal-insulator behavior in LaTiO3/SrTiO3 heterostructures integrated directly on Si(100) through control of atomic layer thickness

Journal Article Applied Physics Letters · May 7, 2018 We present electrical and structural characterization of epitaxial LaTiO3/SrTiO3 heterostructures integrated directly on Si(100). By reducing the thicknesses of the heterostructures, an enhancement in carrier-carrier scattering is observed in the Fermi liq ... Full text Cite

Single Atomic Layer Ferroelectric on Silicon.

Journal Article Nano letters · January 2018 A single atomic layer of ZrO2 exhibits ferroelectric switching behavior when grown with an atomically abrupt interface on silicon. Hysteresis in capacitance-voltage measurements of a ZrO2 gate stack demonstrate that a reversible polar ... Full text Cite

Structural distortions at polar manganite interfaces

Journal Article Physical Review B · July 31, 2017 Electronic, lattice, and spin interactions at the interfaces between crystalline complex transition-metal oxides can give rise to a wide range of functional electronic and magnetic phenomena not found in bulk. At heterointerfaces, these interactions may be ... Full text Cite

Control of hidden ground-state order in NdNi O3 superlattices

Journal Article Physical Review Materials · July 27, 2017 The combination of charge and spin degrees of freedom with electronic correlations in condensed matter systems leads to a rich array of phenomena, such as magnetism, superconductivity, and novel conduction mechanisms. While such phenomena are observed in b ... Full text Cite

Electrically coupling complex oxides to semiconductors: A route to novel material functionalities

Journal Article Journal of Materials Research · January 27, 2017 Complex oxides and semiconductors exhibit distinct yet complementary properties owing to their respective ionic and covalent natures. By electrically coupling complex oxides to traditional semiconductors within epitaxial heterostructures, enhanced or novel ... Full text Cite

Role of double Ti O2 layers at the interface of FeSe/ SrTi O3 superconductors

Journal Article Physical Review B · May 16, 2016 We determine the surface reconstruction of SrTiO3 used to achieve superconducting FeSe films in experiments, which is different from the 1×1TiO2-terminated SrTiO3 assumed by most previous theoretical studies. In particular, we identify the existence of a d ... Full text Cite

Engineered Unique Elastic Modes at a BaTiO_{3}/(2×1)-Ge(001) Interface.

Journal Article Physical review letters · March 2016 The strong interaction at an interface between a substrate and thin film leads to epitaxy and provides a means of inducing structural changes in the epitaxial film. These induced material phases often exhibit technologically relevant electronic, magnetic, ... Full text Cite

Electrically coupling multifunctional oxides to semiconductors: A route to novel material functionalities

Conference MRS Advances · January 1, 2016 Complex oxides and semiconductors exhibit distinct yet complementary properties owing to their respective ionic and covalent natures. By electrically coupling oxides to semiconductors within epitaxial heterostructures, enhanced or novel functionalities bey ... Full text Cite

Oxide 2D electron gases as a route for high carrier densities on (001) Si

Journal Article Applied Physics Letters · May 18, 2015 Two dimensional electron gases (2DEGs) formed at the interfaces of oxide heterostructures draw considerable interest owing to their unique physics and potential applications. Growing such heterostructures on conventional semiconductors has the potential to ... Full text Cite

Orbital engineering in symmetry-breaking polar heterostructures.

Journal Article Physical review letters · January 2015 We experimentally demonstrate a novel approach to substantially modify orbital occupations and symmetries in electronically correlated oxides. In contrast to methods using strain or confinement, this orbital tuning is achieved by exploiting charge transfer ... Full text Cite

Effect of surface termination on the electronic properties of LaNiO3 films

Journal Article Physical Review Applied · November 6, 2014 The electronic and structural properties of thin LaNiO3 films grown by using molecular beam epitaxy are studied as a function of the net ionic charge of the surface terminating layer. We demonstrate that electronic transport in nickelate heterostructures c ... Full text Cite

A high density two-dimensional electron gas in an oxide heterostructure on Si (001)

Journal Article APL Materials · November 1, 2014 We present the growth and characterization of layered heterostructures comprised of LaTiO3 and SrTiO3 epitaxially grown on Si (001). Magnetotransport measurements show that the sheet carrier densities of the heterostructures scale with the number of LaTiO3 ... Full text Cite

Hysteretic electrical transport in BaTiO3/Ba1-xSrxTiO3/Ge heterostructures

Journal Article Applied Physics Letters · October 2, 2014 We present electrical transport measurements of heterostructures comprised of BaTiO3 and Ba1-xSrxTiO3 epitaxially grown on Ge. Sr alloying imparts compressive strain to the BaTiO3, which enables the thermal expansion mismatch between BaTiO3 and Ge to be ov ... Full text Cite

Active silicon integrated nanophotonics: ferroelectric BaTiO₃ devices.

Journal Article Nano letters · March 2014 The integration of complex oxides on silicon presents opportunities to extend and enhance silicon technology with novel electronic, magnetic, and photonic properties. Among these materials, barium titanate (BaTiO3) is a particularly strong ferroelectric pe ... Full text Cite

Tuning the structure of nickelates to achieve two-dimensional electron conduction.

Journal Article Advanced materials (Deerfield Beach, Fla.) · March 2014 Metallic electronic transport in nickelate heterostructures can be induced and confined to two dimensions (2D) by controlling the structural parameters of the nickel-oxygen planes. ... Full text Cite

A silicon integrated BaTiO3 electro-optic modulator

Conference Conference on Lasers and Electro-Optics Europe - Technical Digest · January 1, 2014 A Si-integrated modulator based on epitaxial ferroelectric BaTiO3 thin films is demonstrated with gigahertz modulation bandwidth and an effective Pockels coefficient of 213 ± 49 pm/V. ... Cite

A silicon integrated BaTiO3 electro-optic modulator

Conference Optics InfoBase Conference Papers · January 1, 2014 A Si-integrated modulator based on epitaxial ferroelectric BaTiO3 thin films is demonstrated with gigahertz modulation bandwidth and an effective Pockels coefficient of 213 ± 49 pm/V. © 2014 OSA. ... Full text Cite

Modifying the electronic orbitals of nickelate heterostructures via structural distortions.

Journal Article Physical review letters · May 2013 We describe a general materials design approach that produces large orbital energy splittings (orbital polarization) in nickelate heterostructures, creating a two-dimensional single-band electronic surface at the Fermi energy. The resulting electronic stru ... Full text Cite

Phase diagram of compressively strained nickelate thin films

Journal Article APL Materials · January 1, 2013 The complex phase diagrams of strongly correlated oxides arise from the coupling between physical and electronic structure. This can lead to a renormalization of the phase boundaries when considering thin films rather than bulk crystals due to reduced dime ... Full text Cite

La-doped BaTiO3 heterostructures: Compensating the polarization discontinuity

Journal Article APL Materials · January 1, 2013 We demonstrate a route to manipulate the polarization and internal electric field of a complex oxide heterostructure using a layering sequence based on the LaAlO3-SrTiO3 interface. By combining sensitive atomic-level mapping of the structure using direct x ... Full text Cite

Role of epitaxial strain on the magnetic structure of Fe-doped CoFe 2O4

Journal Article Journal of Magnetism and Magnetic Materials · January 1, 2013 The magnetic structure of Fe-doped CoFe2O4 (Co 1-xFe2+xO4) grown on MgO (0 0 1) and SrTiO 3 (0 0 1) substrates is studied with superconducting quantum interference device magnetometry and soft x-ray magnetic spectroscopies. X-ray and electron diffraction s ... Full text Cite

Enhanced magnetic moment in ultrathin Fe-doped CoFe 2O 4 films

Journal Article Physical Review B - Condensed Matter and Materials Physics · November 5, 2012 The effect of film thickness on the magnetic properties of ultrathin Fe-doped cobalt ferrite (Co 1-xFe 2+xO 4) grown on MgO (001) substrates is investigated by superconducting quantum interference device magnetometry and x-ray magnetic linear dichroism, wh ... Full text Cite

Piezoelectric force microscopy of crystalline oxide-semiconductor heterostructures

Journal Article Applied Physics Letters · September 3, 2012 Thin films of epitaxial SrTiO 3 grown on silicon exhibit compressive in-plane strain that may stabilize ferroelectricity in this normally non-ferroelectric material. We investigate this possibility by using an ultra-high vacuum atomic force microscope to m ... Full text Cite

Epitaxial strain-induced changes in the cation distribution and resistivity of Fe-doped CoFe 2O 4

Journal Article Applied Physics Letters · July 9, 2012 The distribution of cations in Fe-doped cobalt ferrite (Co 1-xFe 2xO 4) is investigated as a function of epitaxial strain through x-ray absorption measurements of samples grown on SrTiO 3, MgO, and CoCr 2O 4-buffered MgAl 2O 4 (001). In agreement with rece ... Full text Cite

Magnetic structure of Fe-doped CoFe2O4 probed by x-ray magnetic spectroscopies

Journal Article Physical Review B - Condensed Matter and Materials Physics · August 15, 2011 The magnetic properties of iron-doped cobalt ferrite (Co 1-xFe2+xO4) (001) thin films grown epitaxially on MgO (001) substrates are investigated by superconducting quantum interference device magnetometry and soft x-ray magnetic linear and circular dichroi ... Full text Cite

Structure of droplet-epitaxy-grown InAs/GaAs quantum dots

Journal Article Applied Physics Letters · June 13, 2011 We have used a direct x-ray phasing method, coherent Bragg rod analysis, to obtain sub-angstrom resolution electron density maps of the InAs/GaAs dot system. The dots were grown by the droplet heteroepitaxy (DHE) technique and their structural and composit ... Full text Cite

Correlating structure, strain, and morphology of self-assembled InAs quantum dots on GaAs

Journal Article Applied Physics Letters · January 10, 2011 We report on the use of a direct x-ray phase retrieval method, coherent Bragg rod analysis, to characterize self-assembled InAs quantum dots (QDs) grown epitaxially on GaAs substrates. Electron density maps obtained close to the x-ray absorption edges of t ... Full text Cite

Surface x-ray diffraction results on the III-V droplet heteroepitaxy growth process for quantum dots: recent understanding and open questions.

Journal Article Sensors (Basel, Switzerland) · January 2011 In recent years, epitaxial growth of self-assembled quantum dots has offered a way to incorporate new properties into existing solid state devices. Although the droplet heteroepitaxy method is relatively complex, it is quite relaxed with respect to the mat ... Full text Cite

The atomic structure and polarization of strained SrTiO3/Si

Journal Article Applied Physics Letters · December 20, 2010 For thin film devices based on coupling ferroelectric polarization to charge carriers in semiconductors, the role of the interface is critical. To elucidate this role, we use synchrotron x-ray diffraction to determine the interface structure of epitaxial S ... Full text Cite

Atomic-scale mapping of quantum dots formed by droplet epitaxy.

Journal Article Nature nanotechnology · December 2009 Quantum dots (QDs) have applications in optoelectronic devices, quantum information processing and energy harvesting. Although the droplet epitaxy fabrication method allows for a wide range of material combinations to be used, little is known about the gro ... Full text Cite

Surface x-ray diffraction of complex metal oxide surfaces and interfaces - a new era

Conference AIP Conference Proceedings · April 23, 2009 The availability of high-brilliance hard x-ray synchrotron radiation and the advent of novel photon counting area detectors have brought surface x-ray diffraction (SXRD) into a new era. It is now possible to record large numbers of structure factors with m ... Full text Cite

Mapping single-crystal dendritic microstructure and defects in nickel-base superalloys with synchrotron radiation

Journal Article Acta Materialia · October 1, 2008 Solidification of single-crystal nickel-base superalloys introduces large-scale segregation of constituent elements and defects such as dislocations and mosaicity. By exploiting the energy tunability and interference capabilities of high-brilliance X-ray r ... Full text Cite

Resonant coherent Bragg rod analysis of strained epitaxial heterostructures

Journal Article Applied Physics Letters · September 15, 2008 The resonant response of the complex x-ray scattering factor has been used in conjunction with the coherent Bragg rod analysis phase-retrieval algorithm to determine the composition and strain profiles of ultrathin layers of GaAs grown on InGaAs buffers. T ... Full text Cite

Strain and composition mapping of epitaxial nanostructures

Journal Article Applied Physics Letters · April 24, 2008 We have used surface x-ray diffraction and a direct method of phase reconstruction to obtain subangström resolution maps of an ion-beam milled In0.27 Ga0.73 AsGaAs (001) thin film exhibiting three-dimensional (3D) epitaxial nanostructures. The 3D electron ... Full text Cite

Structure determination of monolayer-by-monolayer grown La1-x Srx MnO3 thin films and the onset of magnetoresistance

Journal Article Physical Review B - Condensed Matter and Materials Physics · February 1, 2008 Surface x-ray diffraction was used to determine the atomic structures of La1-x Srx MnO3 thin films, grown monolayer by monolayer on SrTiO3 by pulsed laser deposition. Structures for one-, two-, three-, four-, six-, and nine-monolayer-thick films were solve ... Full text Cite

In situ imaging of high cycle fatigue crack growth in single crystal nickel-base superalloys by synchrotron X-radiation

Conference Journal of Engineering Materials and Technology · January 1, 2008 A novel X-ray synchrotron radiation approach is described for real-time imaging of the initiation and growth of fatigue cracks during ultrasonic fatigue (f=20 kHz). We report here on new insights on single crystal nickel-base superalloys gained with this a ... Full text Cite

Surface plasmon resonance effects in the Magneto Optical activity of noble metal-ferro magnet ultrathin films

Conference Conference on Lasers and Electro-Optics Europe - Technical Digest · December 1, 2007 Full text Cite

Structural basis for the conducting interface between LaAlO3 and SrTiO3.

Journal Article Physical review letters · October 2007 The complete atomic structure of a five-monolayer film of LaAlO3 on SrTiO3 has been determined for the first time by surface x-ray diffraction in conjunction with the coherent Bragg rod analysis phase-retrieval method and further structural refinement. Cat ... Full text Cite

Optimizing the planar structure of (1 1 1) Au/Co/Au trilayers

Journal Article Journal of Physics D: Applied Physics · May 7, 2007 Au/Co/Au trilayers are interesting for a range of applications which exploit their unusual optical and electronic transport behaviour in a magnetic field. Here we present a comprehensive structural and morphological study of a series of trilayers with 0-7 ... Full text Cite

Spatial coherence properties of a compact and ultrafast laser-produced plasma keV x-ray source

Journal Article Applied Physics Letters · January 15, 2007 The authors use Fresnel diffraction from knife-edges to demonstrate the spatial coherence of a tabletop ultrafast x-ray source produced by laser-plasma interaction. Spatial coherence is achieved in the far field by producing micrometer-scale x-ray spot dim ... Full text Cite

Surface-magnetoplasmon nonreciprocity effects in noble-metal/ferromagnetic heterostructures

Journal Article Physical Review B - Condensed Matter and Materials Physics · January 1, 2007 We demonstrate magnetic field control of surface plasmon excitations in noble-metal/ferromagnetic/noble metal trilayers, analogous to the effects previously observed in semiconductor structures. We show that the coupling of an external magnetic field to th ... Full text Cite

Demonstration of spatial coherence with a compact and ultrafast x-ray source

Conference Conference on Lasers and Electro-Optics and 2006 Quantum Electronics and Laser Science Conference, CLEO/QELS 2006 · December 1, 2006 We used Fresnel diffraction from knife-edges to demonstrate spatial coherence of tabletop and ultrafast X-ray sources produced by laser-plasma interaction, and show that source size is limited by the spatial spread of absorbed laser energy. © 2006 Optical ... Full text Cite