|
“An electrochemical impedimetric aptasensing platform for sensitive and selective detection of small molecules such as chloramphenicol”. Pilehvar S, Dierckx T, Blust R, Breugelmans T, De Wael K, Sensors 14, 12059 (2014). http://doi.org/10.3390/S140712059
Abstract: We report on the aptadetection of chloramphenicol (CAP) using electrochemical impedance spectroscopy. The detection principle is based on the changes of the interfacial properties of the electrode after the interaction of the ssDNA aptamers with the target molecules. The electrode surface is partially blocked due to the formation of the aptamer-CAP complex, resulting in an increase of the interfacial electron-transfer resistance of the redox probe detected by electrochemical impedance spectroscopy or cyclic voltammetry. We observed that the ratio of polarization resistance had a linear relationship with the concentrations of CAP in the range of 1.76127 nM, and a detection limit of 1.76 nM was obtained. The covalent binding of CAP-aptamer on the electrode surface combined with the unique properties of aptamers and impedimetric transduction leads to the development of a stable and sensitive electrochemical aptasensor for CAP.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Applied Electrochemistry & Catalysis (ELCAT)
Impact Factor: 2.677
Times cited: 34
DOI: 10.3390/S140712059
|
|
“Tuning the intrinsic anisotropy with disorder in the CaKFE₄As₄, superconductor”. Torsello D, Ummarino GA, Bekaert J, Gozzelino L, Gerbaldo R, Tanatar MA, Canfield PC, Prozorov R, Ghigo G, Physical Review Applied 13, 064046 (2020). http://doi.org/10.1103/PHYSREVAPPLIED.13.064046
Abstract: We report on the anisotropy of the London penetration depth of CaKFe4As4, discussing how it relates to its electronic structure and how it modifies under introduction of disorder, both chemically induced (by Ni substitution) and irradiation induced (by 3.5-MeV protons). Indeed, CaKFe4As4 is particularly suitable for the study of fundamental superconducting properties due to its stoichiometric composition, exhibiting clean-limit behavior in the pristine samples and having a fairly high critical temperature, T-c approximate to 35 K. The London penetration depth lambda(L) is measured with a microwave-coplanar-resonator technique that allows us to deconvolve the anisotropic contributions lambda(L,ab) and lambda(L,c) and obtain the anisotropy parameter gamma(lambda) = lambda(L,c)/lambda(L,ab). The gamma(lambda) (T) found for the undoped pristine sample is in good agreement with previous literature and is here compared to ab initio density-functional-theory and Eliashberg calculations. The dependence of gamma(lambda) (T) on both chemical and irradiation-induced disorder is discussed to highlight which method is more suitable to decrease the direction dependence of the electromagnetic properties while maintaining a high critical temperature. Lastly, the relevance of an intrinsic anisotropy such as gamma(lambda) on application-related anisotropic parameters (critical current, pinning) is discussed in light of the recent employment of CaKFe4As4 in the production of wires.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 4.6
Times cited: 4
DOI: 10.1103/PHYSREVAPPLIED.13.064046
|
|
“Pyramid-Shaped Wurtzite CdSe Nanocrystals with Inverted Polarity”. Ghosh S, Gaspari R, Bertoni G, Spadaro MC, Prato M, Turner S, Cavalli A, Manna L, Brescia R, ACS nano 9, 8537 (2015). http://doi.org/10.1021/acsnano.5b03636
Abstract: We report on pyramid-shaped wurtzite cadmium selenide (CdSe) nanocrystals (NCs), synthesized by hot injection in the presence of chloride ions as shape-directing agents, exhibiting reversed crystal polarity compared to former reports. Advanced transmission electron microscopy (TEM) techniques (image-corrected high-resolution TEM with exit wave reconstruction and probe-corrected high-angle annular dark field-scanning TEM) unequivocally indicate that the triangular base of the pyramids is the polar (0001) facet and their apex points toward the [0001] direction. Density functional theory calculations, based on a simple model of binding of Cl(-) ions to surface Cd atoms, support the experimentally evident higher thermodynamic stability of the (0001) facet over the (0001) one conferred by Cl(-) ions. The relative stability of the two polar facets of wurtzite CdSe is reversed compared to previous experimental and computational studies on Cd chalcogenide NCs, in which no Cl-based chemicals were deliberately used in the synthesis or no Cl(-) ions were considered in the binding models. Self-assembly of these pyramids in a peculiar clover-like geometry, triggered by the addition of oleic acid, suggests that the basal (polar) facet has a density and perhaps type of ligands significantly different from the other three facets, since the pyramids interact with each other exclusively via their lateral facets. A superstructure, however with no long-range order, is observed for clovers with their (0001) facets roughly facing each other. The CdSe pyramids were also exploited as seeds for CdS pods growth, and the peculiar shape of the derived branched nanostructures clearly arises from the inverted polarity of the seeds.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 13.942
Times cited: 16
DOI: 10.1021/acsnano.5b03636
|
|
“Tailoring CuO nanostructures for enhanced photocatalytic property”. Liu J, Jin J, Deng Z, Huang SZ, Hu ZY, Wang L, Wang C, Chen LH, Li Y, Van Tendeloo G, Su BL;, Journal of colloid and interface science 384, 1 (2012). http://doi.org/10.1016/j.jcis.2012.06.044
Abstract: We report on one-pot synthesis of various morphologies of CuO nanostructures. PEG200 as a structure directing reagent under the synergism of alkalinity by hydrothermal method has been employed to tailor the morphology of CuO nanostructures. The CuO products have been characterized by XRD, SEM, and TEM. The morphologies of the CuO nanostructures can be tuned from 10 (nanoseeds, nanoribbons) to 2D (nanoleaves) and to 3D (shuttle-like, shrimp-like, and nanoflowers) by changing the volume of PEG200 and the alkalinity in the reaction system. At neutral and relatively low alkalinity (OH-/Cu2+ <= 3), the addition of PEG200 can strongly influence the morphologies of the CuO nanostructures. At high alkalinity (OH/Cu2+ >= 4), PEG200 has no influence on the morphology of the CuO nanostructure. The different morphologies of the CuO nanostructures have been used for the photodecomposition of the pollutant rhodamine B (RhB) in water. The photocatalytic activity has been correlated with the different nanostructures of CuO. The 10 CuO nanoribbons exhibit the best performance on the RhB photodecomposition because of the exposed high surface energy {-121} crystal plane. The photocatalytic results show that the high energy surface planes of the CuO nanostructures mostly affect the photocatalytic activity rather than the morphology of the CuO nanostructures. Our synthesis method also shows it is possible to control the morphologies of nanostructures in a simple way. (C) 2012 Elsevier Inc. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.233
Times cited: 105
DOI: 10.1016/j.jcis.2012.06.044
|
|
“Effect of head group and lipid tail oxidation in the cell membrane revealed through integrated simulations and experiments”. Yusupov M, Wende K, Kupsch S, Neyts EC, Reuter S, Bogaerts A, Scientific reports 7, 5761 (2017). http://doi.org/10.1038/s41598-017-06412-8
Abstract: We report on multi-level atomistic simulations for the interaction of reactive oxygen species (ROS) with the head groups of the phospholipid bilayer, and the subsequent effect of head group and lipid tail oxidation on the structural and dynamic properties of the cell membrane. Our simulations are validated by experiments using a cold atmospheric plasma as external ROS source. We found that plasma treatment leads to a slight initial rise in membrane rigidity, followed by a strong and persistent increase in fluidity, indicating a drop in lipid order. The latter is also revealed by our simulations. This study is important for cancer treatment by therapies producing (extracellular) ROS, such as plasma treatment. These ROS will interact with the cell membrane, first oxidizing the head groups, followed by the lipid tails. A drop in lipid order might allow them to penetrate into the cell interior (e.g., through pores created due to oxidation of the lipid tails) and cause intracellular oxidative damage, eventually leading to cell death. This work in general elucidates the underlying mechanisms of ROS interaction with the cell membrane at the atomic level.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.259
Times cited: 27
DOI: 10.1038/s41598-017-06412-8
|
|
“Precision magnetometry on a submicron scale: magnetisation of superconducting quantum dots”. Geim AK, Grigorieva IV, Lok JGS, Maan JC, Dubonos SV, Li XQ, Peeters FM, Nazarov YV, Superlattices and microstructures 23, 151 (1998). http://doi.org/10.1006/spmi.1996.0199
Abstract: We report on magnetisation of individual superconducting particles with size down to 0.1 micron. The non-invasive access to properties of such small objects has become possible using submicron Hall probes which detect a local magnetic field and work effectively as micro-fluxmeters similar to, e.g., SQUIDs but with an effective detection loop of only about a square micron. We have found that the spatial confinement of superconductivity in a small volume gives rise to dramatic changes in thermodynamic properties of mesoscopic superconductors. (C) 1998 Academic Press Limited.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.123
Times cited: 12
DOI: 10.1006/spmi.1996.0199
|
|
“In situ TEM observation of cooperative grain rotations and the Bauschinger effect in nanocrystalline palladium”. Kashiwar A, Hahn H, Kubel C, Nanomaterials 11, 432 (2021). http://doi.org/10.3390/NANO11020432
Abstract: We report on cooperative grain rotation accompanied by a strong Bauschinger effect in nanocrystalline (nc) palladium thin film. A thin film of nc Pd was subjected to cyclic loading-unloading using in situ TEM nanomechanics, and the evolving microstructural characteristics were investigated with ADF-STEM imaging and quantitative ACOM-STEM analysis. ADF-STEM imaging revealed a partially reversible rotation of nanosized grains with a strong out-of-plane component during cyclic loading-unloading experiments. Sets of neighboring grains were shown to rotate cooperatively, one after the other, with increasing/decreasing strain. ACOM-STEM in conjunction with these experiments provided information on the crystallographic orientation of the rotating grains at different strain levels. Local Nye tensor analysis showed significantly different geometrically necessary dislocation (GND) density evolution within grains in close proximity, confirming a locally heterogeneous deformation response. The GND density analysis revealed the formation of dislocation pile-ups at grain boundaries (GBs), indicating the generation of back stresses during unloading. A statistical analysis of the orientation changes of individual grains showed the rotation of most grains without global texture development, which fits to both dislocation- and GB sliding-based mechanisms. Overall, our quantitative in situ experimental approach explores the roles of these different deformation mechanisms operating in nanocrystalline metals during cyclic loading.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.553
DOI: 10.3390/NANO11020432
|
|
“Electrochemical fingerprint of street samples for fast on-site screening of cocaine in seized drug powders”. De Jong M, Sleegers N, Kim J, Van Durme F, Samyn N, Wang J, De Wael K, Chemical science , 1 (2016). http://doi.org/10.1039/C5SC04309C
Abstract: We report on a wearable fingertip sensor for on-the-spot identification of cocaine and its cutting agents in street samples. Traditionally, on-site screening is performed by means of colour tests which are difficult to interpret and lack selectivity. By presenting the distinct voltammetric response of cocaine, cutting agents, binary mixtures of cocaine and street samples in solution and powder street samples, we were able to elucidate the electrochemical fingerprint of all these compounds. The new electrochemical concept holds considerable promise as an on-site screening method.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 8.668
Times cited: 37
DOI: 10.1039/C5SC04309C
|
|
“Ciliary white light : optical aspect of ultrashort laser ablation on transparent dielectrics”. Liu Y, Brelet Y, He Z, Yu L, Mitryukovskiy S, Houard A, Forestier B, Couairon A, Mysyrowicz A, Physical review letters 110, 097601 (2013). http://doi.org/10.1103/PhysRevLett.110.097601
Abstract: We report on a novel nonlinear optical phenomenon, coined as ciliary white light, during laser ablation of transparent dielectrics. It is observed in 14 different transparent materials including glasses, crystals, and polymers. This phenomenon is also universal with respect to laser polarization, pulse duration, and focusing geometry. We interpret its formation in terms of the nonlinear diffraction of the laser generated white light by the ablation crater covered by nanostructures. It carries rich information on the damage profile and morphology dynamics of the ablated surface, providing a real time in situ observation of the laser ablation process. DOI: 10.1103/PhysRevLett.110.097601
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 8.462
Times cited: 10
DOI: 10.1103/PhysRevLett.110.097601
|
|
“A comprehensive modelling approach for the neutral atmospheric boundary layer : consistent inflow conditions, wall function and turbulence model”. Parente A, Gorlé, C, van Beeck J, Benocci C, Boundary-layer meteorology 140, 411 (2011). http://doi.org/10.1007/s10546-011-9621-5
Abstract: We report on a novel approach for the Reynolds-averaged Navier-Stokes (RANS) modelling of the neutral atmospheric boundary layer (ABL), using the standard k− turbulence model. A new inlet condition for turbulent kinetic energy is analytically derived from the solution of the k− model transport equations, resulting in a consistent set of fully developed inlet conditions for the neutral ABL. A modification of the standard k− model is also employed to ensure consistency between the inlet conditions and the turbulence model. In particular, the turbulence model constant C μ is generalized as a location-dependent parameter, and a source term is introduced in the transport equation for the turbulent dissipation rate. The application of the proposed methodology to cases involving obstacles in the flow is made possible through the implementation of an algorithm, which automatically switches the turbulence model formulation when going from the region where the ABL is undisturbed to the region directly affected by the building. Finally, the model is completed with a slightly modified version of the Richards and Hoxey rough-wall boundary condition. The methodology is implemented and tested in the commercial code Ansys Fluent 12.1. Results are presented for a neutral boundary layer over flat terrain and for the flow around a single building immersed in an ABL.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.573
Times cited: 54
DOI: 10.1007/s10546-011-9621-5
|
|
“Multistep radial melting in small two-dimensional classical clusters”. Tomecka D, Partoens B, Peeters FM, Physical review : E : statistical physics, plasmas, fluids, and related interdisciplinary topics 71, 062401 (2005). http://doi.org/10.1103/PhysRevE.71.062401
Abstract: We report on a molecular dynamics study of small classical two-dimensional clusters with ringlike configurations. We focus on the particles motion at low temperatures before the radial and angular melting sets in. It is shown that in magic number configurations a local radial melting of subshells occur, which is related to the intershell rotation.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.366
Times cited: 11
DOI: 10.1103/PhysRevE.71.062401
|
|
“Structural and electronic properties of defects at grain boundaries in CuInSe2”. Saniz R, Bekaert J, Partoens B, Lamoen D, Physical chemistry, chemical physics 19, 14770 (2017). http://doi.org/10.1039/C7CP02033C
Abstract: We report on a first-principles study of the structural and electronic properties of a Sigma3 (112) grain boundary model in CuInSe2. The study focuses on a coherent, stoichiometry preserving, cation–Se terminated grain boundary, addressing the properties of the grain boundary as such, as well as the effect
of well known defects in CuInSe2. We show that in spite of its apparent simplicity, such a grain boundary exhibits a very rich phenomenology, providing an explanation for several of the experimentally observed properties of grain boundaries in CuInSe2 thin films. In particular, we show that the combined effect of Cu vacancies and cation antisites can result in the observed Cu depletion with no In enrichment at the grain boundaries. Furthermore, Cu vacancies are unlikely to produce a hole barrier at the grain boundaries, but Na may indeed have such an effect. We find that Na-on-Cu defects will tend to form abundantly at
the grain boundaries, and can provide a mechanism for the carrier depletion and/or type inversion experimentally reported.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Impact Factor: 4.123
Times cited: 12
DOI: 10.1039/C7CP02033C
|
|
“Surface Functionalization of Grown-on-Tip ZnO Nanopyramids: From Fabrication to Light-Triggered Applications”. Gasparotto A, Maccato C, Carraro G, Sada C, Štangar UL, Alessi B, Rocks C, Mariotti D, La Porta A, Altantzis T, Barreca D, Acs Applied Materials &, Interfaces 11, 15881 (2019). http://doi.org/10.1021/acsami.8b22744
Abstract: We report on a combined chemical vapor deposition (CVD)/radio frequency (RF) sputtering synthetic strategy for the controlled surface modification of ZnO nanostructures by Ti-containing species. Specifically, the proposed approach consists in the CVD of grown-on-tip ZnO nanopyramids, followed by titanium RF sputtering under mild conditions. The results obtained by a thorough characterization demonstrate the successful ZnO surface functionalization with dispersed Ti-containing species in low amounts. This phenomenon, in turn, yields a remarkable enhancement of photoactivated superhydrophilic behavior, self-cleaning ability, and photocatalytic performances in comparison to bare ZnO. The reasons accounting for such an improvement are unravelled by a multitechnique analysis, elucidating the interplay between material chemico-physical properties and the corresponding functional behavior. Overall, the proposed strategy stands as an amenable tool for the mastering of semiconductor-based functional nanoarchitectures through ad hoc engineering of the system surface.
Keywords: A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Impact Factor: 7.504
Times cited: 1
DOI: 10.1021/acsami.8b22744
|
|
“Electronic transport mechanisms correlated to structural properties of a reduced graphene oxide sponge”. Pinto N, McNaughton B, Minicucci M, Milošević, MV, Perali A, Nanomaterials 11, 2503 (2021). http://doi.org/10.3390/NANO11102503
Abstract: We report morpho-structural properties and charge conduction mechanisms of a foamy “graphene sponge ”, having a density as low as & AP;0.07 kg/m3 and a carbon to oxygen ratio C:O & SIME; 13:1. The spongy texture analysed by scanning electron microscopy is made of irregularly-shaped millimetres-sized small flakes, containing small crystallites with a typical size of & SIME;16.3 nm. A defect density as high as & SIME;2.6 x 1011 cm-2 has been estimated by the Raman intensity of D and G peaks, dominating the spectrum from room temperature down to & SIME;153 K. Despite the high C:O ratio, the graphene sponge exhibits an insulating electrical behavior, with a raise of the resistance value at & SIME;6 K up to 5 orders of magnitude with respect to the room temperature value. A variable range hopping (VRH) conduction, with a strong 2D character, dominates the charge carriers transport, from 300 K down to 20 K. At T < 20 K, graphene sponge resistance tends to saturate, suggesting a temperature-independent quantum tunnelling. The 2D-VRH conduction originates from structural disorder and is consistent with hopping of charge carriers between sp2 defects in the plane, where sp3 clusters related to oxygen functional groups act as potential barriers.</p>
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 3.553
DOI: 10.3390/NANO11102503
|
|
“Spontaneous vortex phases in superconductor-ferromagnet Pb-Co nanocomposite films”. Xing YT, Micklitz H, Rappoport TG, Milošević, MV, Solorzano-Naranjo IG, Baggio-Saitovitch E, Physical review : B : solid state 78, 224524 (2008). http://doi.org/10.1103/PhysRevB.78.224524
Abstract: We report measurements which indicate the appearance of spontaneous vortices in lead superconducting films with embedded magnetic nanoparticles and a temperature-induced phase transition between different vortex phases. Unlike common vortices in superconductors, the vortex phase appears in the absence of applied magnetic field. The vortices nucleate exclusively due to the stray field of the magnetic nanoparticles, which serve the dual role of providing the internal field and simultaneously acting as pinning centers. Transport measurements reveal dynamical phase transitions that depend on temperature (T) and applied field (H) and support the obtained H-T phase diagram.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 15
DOI: 10.1103/PhysRevB.78.224524
|
|
“Determining the molecular orientation on the metal nanoparticle surface through surface-enhanced Raman spectroscopy and density functional theory simulations”. Akbali B, Yagmurcukardes M, Peeters FM, Lin H-Y, Lin T-Y, Chen W-H, Maher S, Chen T-Y, Huang C-H, Journal Of Physical Chemistry C 125, 16289 (2021). http://doi.org/10.1021/ACS.JPCC.1C03931
Abstract: We report here the efficacy of surface-enhanced Raman spectroscopy (SERS) measurements as a probe for molecular orientation. 4-Aminobenzoic acid (PABA) on a surface consisting of silver (Ag) nanoparticles (NPs) is investigated. We find that the orientation of the PABA molecule on the SERS substrate is estimated based on the relative change in the magnitude of the C-H stretching bands on the SERS substrate, and it is found that the molecule assumes a horizontal orientation on the Ag-NP surface. The strong molecule-metal interaction is determined by an abnormal enhanced SERS band appearing at 980 cm(-1), and the peak is assigned to an out-of-plane amine vibrational mode, which is supported by our ab initio calculations. DFT-based Raman activity calculations corroborate the SERS results, revealing that (i) the PABA molecule attaches to the surface of Ag-NPs with its alpha dimers rather than single-molecule binding and (ii) the molecule preserves its alpha dimers in an aqueous environment. Our results demonstrate that SERS can be used to gain deeper insights into the molecular orientation on metal nanoparticle surfaces.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 4.536
Times cited: 9
DOI: 10.1021/ACS.JPCC.1C03931
|
|
“Fast A-site cation cross-exchange at room temperature : single-to double- and triple-cation halide perovskite nanocrystals”. Otero-Martinez C, Imran M, Schrenker NJ, Ye J, Ji K, Rao A, Stranks SD, Hoye RLZ, Bals S, Manna L, Perez-Juste J, Polavarapu L, Angewandte Chemie: international edition in English 61, e202205617 (2022). http://doi.org/10.1002/ANIE.202205617
Abstract: We report here fast A-site cation cross-exchange between APbX(3) perovskite nanocrystals (NCs) made of different A-cations (Cs (cesium), FA (formamidinium), and MA (methylammonium)) at room temperature. Surprisingly, the A-cation cross-exchange proceeds as fast as the halide (X=Cl, Br, or I) exchange with the help of free A-oleate complexes present in the freshly prepared colloidal perovskite NC solutions. This enabled the preparation of double (MACs, MAFA, CsFA)- and triple (MACsFA)-cation perovskite NCs with an optical band gap that is finely tunable by their A-site composition. The optical spectroscopy together with structural analysis using XRD and atomically resolved high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and integrated differential phase contrast (iDPC) STEM indicates the homogeneous distribution of different cations in the mixed perovskite NC lattice. Unlike halide ions, the A-cations do not phase-segregate under light illumination.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 16.6
Times cited: 28
DOI: 10.1002/ANIE.202205617
|
|
“Interface-controlled magnetism and transport of ultrathin manganite films”. Shapoval O, Huehn S, Verbeeck J, Jungbauer M, Belenchuk A, Moshnyaga V, Journal of applied physics 113, 17c711 (2013). http://doi.org/10.1063/1.4795422
Abstract: We report ferromagnetic, T-C = 240 K, and metallic, T-MI = 250 K, behaviors of a three unit cell thick interface engineered lanthanum manganite film, grown by metalorganic aerosol deposition technique on SrTiO3(100) substrates. Atomically resolved electron microscopy and chemical analysis show that ultrathin manganite films start to grow with La-O layer on a strongly Mn/Ti-intermixed interface, engineered by an additional deposition of 2 u.c. of Sr-Mn-O. Such interface engineering results in a hole-doped manganite layer and stabilizes ferromagnetism and metallic conductivity down to the thickness of d = 3 u.c. The films with d = 8 u.c. demonstrate a bulk-like transport behavior with T-MI similar to T-C = 310 – 330 K. (C) 2013 American Institute of Physics.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.068
Times cited: 7
DOI: 10.1063/1.4795422
|
|
“Crystal fields, disorder, and antiferromagnetic short-range order in Yb0.24Sn0.76Ru”. Klimczuk T, Wang CH, Lawrence JM, Xu Q, Durakiewicz T, Ronning F, Llobet A, Trouw F, Kurita N, Tokiwa Y, Lee Ho, Booth CH, Gardner JS, Bauer ED, Joyce JJ, Zandbergen HW, Movshovich R, Cava RJ, Thompson JD;, Physical review : B : condensed matter and materials physics 84, 075152 (2011). http://doi.org/10.1103/PhysRevB.84.075152
Abstract: We report extensive measurements on a new compound (Yb0.24Sn0.76)Ru that crystallizes in the cubic CsCl structure. Valence-band photoemission (PES) and L3 x-ray absorption show no divalent component in the 4f configuration of Yb. Inelastic neutron scattering (INS) indicates that the eight-fold degenerate J-multiplet of Yb3+ is split by the crystalline electric field (CEF) into a Γ7-doublet ground state and a Γ8 quartet at an excitation energy 20 meV. The magnetic susceptibility can be fit very well by this CEF scheme under the assumption that a Γ6-excited state resides at 32 meV; however, the Γ8/Γ6 transition expected at 12 meV was not observed in the INS. The resistivity follows a Bloch-Grüneisen law shunted by a parallel resistor, as is typical of systems subject to phonon scattering with no apparent magnetic scattering. All of these properties can be understood as representing simple local moment behavior of the trivalent Yb ion. At 1 K there is a peak in specific heat that is too broad to represent a magnetic-phase transition, consistent with absence of magnetic reflections in neutron diffraction. On the other hand this peak also is too narrow to represent the Kondo effect in the Γ7-doublet ground state. On the basis of the field dependence of the specific heat, we argue that antiferromagnetic (AF) short-range order (SRO) (possibly coexisting with Kondo physics) occurs at low temperatures. The long-range magnetic order is suppressed because the Yb site occupancy is below the percolation threshold for this disordered compound.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 8
DOI: 10.1103/PhysRevB.84.075152
|
|
“Skyrmion-(Anti)Vortex Coupling in a Chiral Magnet-Superconductor Heterostructure”. Petrović, A p, Raju M, Tee X y, Louat A, Maggio-Aprile I, Menezes R m, Wyszyński M j, Duong N k, Reznikov M, Renner C, Milošević, MV, Panagopoulos C, Physical Review Letters 126, 117205 (2021). http://doi.org/10.1103/PhysRevLett.126.117205
Abstract: We report experimental coupling of chiral magnetism and superconductivity in [IrFeCoPt]/Nb heterostructures. The stray field of skyrmions with radius ~50nm is sufficient to nucleate antivortices in a 25nm Nb film, with unique signatures in the magnetization, critical current and flux dynamics, corroborated via simulations. We also detect a thermally-tunable Rashba-Edelstein exchange coupling in the isolated skyrmion phase. This realization of a strongly interacting skyrmion-(anti)vortex system opens a path towards controllable topological hybrid materials, unattainable to date.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 8.462
Times cited: 20
DOI: 10.1103/PhysRevLett.126.117205
|
|
“Peierls distortion, magnetism, and high hardness of manganese tetraboride”. Gou H, Tsirlin AA, Bykova E, Abakumov AM, Van Tendeloo G, Richter A, Ovsyannikov SV, Kurnosov AV, Trots DM, Konôpková, Z, Liermann HP, Dubrovinsky L, Dubrovinskaia N;, Physical review : B : condensed matter and materials physics 89, 064108 (2014). http://doi.org/10.1103/PhysRevB.89.064108
Abstract: We report crystal structure, electronic structure, and magnetism of manganese tetraboride, MnB4, synthesized under high-pressure, high-temperature conditions. In contrast to superconducting FeB4 and metallic CrB4, which are both orthorhombic, MnB4 features a monoclinic crystal structure. Its lower symmetry originates from a Peierls distortion of the Mn chains. This distortion nearly opens the gap at the Fermi level, but despite the strong dimerization and the proximity of MnB4 to the insulating state, we find indications for a sizable paramagnetic effective moment of about 1.7 mu(B)/f.u., ferromagnetic spin correlations, and, even more surprisingly, a prominent electronic contribution to the specific heat. However, no magnetic order has been observed in standard thermodynamic measurements down to 2 K. Altogether, this renders MnB4 a structurally simple but microscopically enigmatic material; we argue that its properties may be influenced by electronic correlations.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 39
DOI: 10.1103/PhysRevB.89.064108
|
|
“Co valence transformation in isopolar LaCoO3/LaTiO3 perovskite heterostructures via interfacial engineering”. Araizi-Kanoutas G, Geessinck J, Gauquelin N, Smit S, Verbeek XH, Mishra SK, Bencok P, Schlueter C, Lee T-L, Krishnan D, Fatermans J, Verbeeck J, Rijnders G, Koster G, Golden MS, Physical review materials 4, 026001 (2020). http://doi.org/10.1103/PhysRevMaterials.4.026001
Abstract: We report charge transfer up to a single electron per interfacial unit cell across nonpolar heterointerfaces from the Mott insulator LaTiO3 to the charge transfer insulator LaCoO3. In high-quality bi- and trilayer systems grown using pulsed laser deposition, soft x-ray absorption, dichroism, and scanning transmission electron microscopy-electron energy loss spectroscopy are used to probe the cobalt-3d electron count and provide an element-specific investigation of the magnetic properties. The experiments show the cobalt valence conversion is active within 3 unit cells of the heterointerface, and able to generate full conversion to 3d7 divalent Co, which displays a paramagnetic ground state. The number of LaTiO3/LaCoO3 interfaces, the thickness of an additional, electronically insulating “break” layer between the LaTiO3 and LaCoO3, and the LaCoO3 film thickness itself in trilayers provide a trio of control knobs for average charge of the cobalt ions in LaCoO3, illustrating the efficacy of O−2p band alignment as a guiding principle for property design in complex oxide heterointerfaces.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.4
Times cited: 13
DOI: 10.1103/PhysRevMaterials.4.026001
|
|
“Skyrmionic chains and lattices in s plus id superconductors”. Zhang L, Zhang Y-Y, Zha G-Q, Milošević, MV, Zhou S-P, Physical Review B 101, 064501 (2020). http://doi.org/10.1103/PHYSREVB.101.064501
Abstract: We report characteristic vortex configurations in s + id superconductors with time-reversal symmetry breaking, exposed to magnetic field. A vortex in the s + id state tends to have an opposite phase winding between s- and d-wave condensates. We find that this peculiar feature together with the competition between s- and d-wave symmetry results in three distinct classes of vortical configurations. When either s or d condensate absolutely dominates, vortices form a conventional lattice. However, when one condensate is relatively dominant, vortices organize in chains that exhibit skyrmionic character, separating the chiral components of the s +/- id order parameter into domains within and outside the chain. Such skyrmionic chains are found stable even at high magnetic field. When s and d condensates have comparable strength, vortices split cores in two chiral components to form full-fledged skyrmions, i.e., coreless topological structures with an integer topological charge, organized in a lattice. We provide characteristic magnetic field distributions of all states, enabling their identification in, e.g., scanning Hall probe and scanning SQUID experiments. These unique vortex states are relevant for high-T-c cuprate and iron-based superconductors, where the relative strength of competing pairing symmetries is expected to be tuned by temperature and/or doping level, and can help distinguish s + is and s + id superconducting phases.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.7
Times cited: 7
DOI: 10.1103/PHYSREVB.101.064501
|
|
“Resistive switching at manganite/manganite interfaces”. Kalkert C, Krisponeit J-O, Esseling M, Lebedev OI, Moshnyaga V, Damaschke B, Van Tendeloo G, Samwer K, Applied physics letters 99, 132512 (2011). http://doi.org/10.1063/1.3643425
Abstract: We report bipolar resistive switching between the interfaces of manganite nanocolumns. La0.7Sr0.3MnO3 films were prepared on Al2O3 substrates, where the films grow in nanocolumns from the substrate to the surface. Conductive atomic force microscopy directly detects that the resistive switching is located at the boundaries of the grains. Furthermore, mesoscopic transport measurements reveal a tunnel magnetoresistance. In combination with the resistive switching, this leads to a total of four different resistive states.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 10
DOI: 10.1063/1.3643425
|
|
“Optimal experimental design for the detection of light atoms from high-resolution scanning transmission electron microscopy images”. Gonnissen J, de Backer A, den Dekker AJ, Martinez GT, Rosenauer A, Sijbers J, Van Aert S, Applied physics letters 105, 063116 (2014). http://doi.org/10.1063/1.4892884
Abstract: We report an innovative method to explore the optimal experimental settings to detect light atoms from scanning transmission electron microscopy (STEM) images. Since light elements play a key role in many technologically important materials, such as lithium-battery devices or hydrogen storage applications, much effort has been made to optimize the STEM technique in order to detect light elements. Therefore, classical performance criteria, such as contrast or signal-to-noise ratio, are often discussed hereby aiming at improvements of the direct visual interpretability. However, when images are interpreted quantitatively, one needs an alternative criterion, which we derive based on statistical detection theory. Using realistic simulations of technologically important materials, we demonstrate the benefits of the proposed method and compare the results with existing approaches.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Impact Factor: 3.411
Times cited: 12
DOI: 10.1063/1.4892884
|
|
“Theoretical and experimental investigation of conjugation of 1,6-hexanedithiol on MoS2”. Gul A, Bacaksiz C, Unsal E, Akbali B, Tomak A, Zareie HM, Sahin H, Materials Research Express 5, 036415 (2018). http://doi.org/10.1088/2053-1591/AAB4A6
Abstract: We report an experimental and theoretical investigation of conjugation of 1,6-Hexaneditihiol (HDT) on MoS2 which is prepared by mixing MoS2 structure and HDT molecules in proper solvent. Raman spectra and the calculated phonon bands reveal that the HDT molecules bind covalently to MoS2. Surface morphology of MoS2/HDTstructure is changed upon conjugation ofHDTon MoS2 and characterized by using Scanning Electron Microscope (SEM). Density Functional Theory (DFT) based calculations show that HOMO-LUMO band gap of HDT is altered after the conjugation and two-S binding (handle-like) configuration is energetically most favorable among three different structures. This study displays that the facile thiol functionalization process of MoS2 is promising strategy for obtaining solution processable MoS2.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.068
Times cited: 2
DOI: 10.1088/2053-1591/AAB4A6
|
|
“Atomic layer epitaxy of Ruddlesden-Popper SrO(SrTiO3)n films by means of metalorganic aerosol deposition”. Jungbauer M, Huehn S, Egoavil R, Tan H, Verbeeck J, Van Tendeloo G, Moshnyaga V, Applied physics letters 105, 251603 (2014). http://doi.org/10.1063/1.4905055
Abstract: We report an atomic layer epitaxial growth of Ruddlesden-Popper (RP) thin films of SrO(SrTiO3)(n) (n = infinity, 2, 3, 4) by means of metalorganic aerosol deposition (MAD). The films are grown on SrTiO3(001) substrates by means of a sequential deposition of Sr-O/Ti-O-2 atomic monolayers, monitored in-situ by optical ellipsometry. X-ray diffraction and transmission electron microscopy (TEM) reveal the RP structure with n = 2-4 in accordance with the growth recipe. RP defects, observed by TEM in a good correlation with the in-situ ellipsometry, mainly result from the excess of SrO. Being maximal at the film/substrate interface, the SrO excess rapidly decreases and saturates after 5-6 repetitions of the SrO(SrTiO3)(4) block at the level of 2.4%. This identifies the SrTiO3 substrate surface as a source of RP defects under oxidizing conditions within MAD. Advantages and limitations of MAD as a solution-based and vacuum-free chemical deposition route were discussed in comparison with molecular beam epitaxy. (C) 2014 AIP Publishing LLC.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 32
DOI: 10.1063/1.4905055
|
|
“Realization of artificial ice systems for magnetic vortices in a superconducting MoGe thin film with patterned nanostructures”. Latimer ML, Berdiyorov GR, Xiao ZL, Peeters FM, Kwok WK, Physical review letters 111, 067001 (2013). http://doi.org/10.1103/PhysRevLett.111.067001
Abstract: We report an anomalous matching effect in MoGe thin films containing pairs of circular holes arranged in such a way that four of those pairs meet at each vertex point of a square lattice. A remarkably pronounced fractional matching was observed in the magnetic field dependences of both the resistance and the critical current. At the half matching field the critical current can be even higher than that at zero field. This has never been observed before for vortices in superconductors with pinning arrays. Numerical simulations within the nonlinear Ginzburg-Landau theory reveal a square vortex ice configuration in the ground state at the half matching field and demonstrate similar characteristic features in the field dependence of the critical current, confirming the experimental realization of an artificial ice system for vortices for the first time.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 8.462
Times cited: 63
DOI: 10.1103/PhysRevLett.111.067001
|
|
“Towards CMOS-compatible single-walled carbon nanotube resonators”. Pathangi H, Cherman V, Khaled A, Sorée B, Groeseneken G, Witvrouw A, Microelectronic engineering 107, 219 (2013). http://doi.org/10.1016/j.mee.2012.06.007
Abstract: We report a totally CMOS-compatible fabrication technique to assemble horizontally suspended single-walled carbon nanotube (SWCNT) resonators. Individual SWCNTs are assembled in parallel at multiple sites by a technique called dielectrophoresis. The mechanical resonance frequencies of the suspended SWCNTs are in the range of 2035 MHz as determined from the piezoresistive response of the resonators during electrostatic actuation. The resistance of the suspended SWCNT either remains unchanged or increases or decreases significantly as a function of the actuation frequency. This can be explained by the effect the nanotube chirality has on the piezoresistive gauge factor.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 1.806
Times cited: 6
DOI: 10.1016/j.mee.2012.06.007
|
|
“Tailoring ZnSe-CdSe colloidal quantum dots via cation exchange : from core/shell to alloy nanocrystals”. Groeneveld E, Witteman L, Lefferts M, Ke X, Bals S, Van Tendeloo G, de Mello Donega C, ACS nano 7, 7913 (2013). http://doi.org/10.1021/nn402931y
Abstract: We report a study of Zn2+ by Cd2+ cation exchange (CE) in colloidal ZnSe nanocrystals (NCs). Our results reveal that CE in ZnSe NCs is a thermally activated isotropic process. The CE efficiency (i.e., fraction of Cd2+ ions originally in solution, Cdsol, that is incorporated in the ZnSe NC) increases with temperature and depends also on the Cdsol/ZnSe ratio. Interestingly, the reaction temperature can be used as a sensitive parameter to tailor both the composition and the elemental distribution profile of the product (Zn,Cd)Se NCs. At 150 °C ZnSe/CdSe core/shell hetero-NCs (HNCs) are obtained, while higher temperatures (200 and 220 °C) produce (Zn1xCdx)Se gradient alloy NCs, with increasingly smoother gradients as the temperature increases, until homogeneous alloy NCs are obtained at T ≥ 240 °C. Remarkably, sequential heating (150 °C followed by 220 °C) leads to ZnSe/CdSe core/shell HNCs with thicker shells, rather than (Zn1xCdx)Se gradient alloy NCs. Thermal treatment at 250 °C converts the ZnSe/CdSe core/shell HNCs into (Zn1xCdx)Se homogeneous alloy NCs, while preserving the NC shape. A mechanism for the cation exchange in ZnSe NCs is proposed, in which fast CE takes place at the NC surface, and is followed by relatively slower thermally activated solid-state cation diffusion, which is mediated by Frenkel defects. The findings presented here demonstrate that cation exchange in colloidal ZnSe NCs provides a very sensitive tool to tailor the nature and localization regime of the electron and hole wave functions and the optoelectronic properties of colloidal ZnSeCdSe NCs.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 13.942
Times cited: 153
DOI: 10.1021/nn402931y
|