Searched for: author:"Pappas, C."
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Kusmin, A. (author), Pappas, C. (author)
Neutron Spin Echo methods (NSE) use Larmor labelling to measure the precession phase of the neutron beam polarization around well-defined magnetic fields. Scattering by a sample can affect the resulting precession phase providing information on the sample's structure and dynamics with high accuracy and resolution. A major limitation for the...
journal article 2020
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Navarro Lopez, A. (author), Ioannidou, C. (author), van der Wal, E.M. (author), Arechabaleta Guenechea, Z. (author), van den Oever, R. (author), Verleg, M.N. (author), Dalgliesh, R. M. (author), Sykora, J. (author), Akeroyd, F. A. (author), Geerlofs, N. (author), Sietsma, J. (author), Pappas, C. (author), van Well, A.A. (author), Offerman, S.E. (author)
Interphase precipitation occurring during solid-state phase transformations in micro-alloyed steels is generally studied through transmission electron microscopy, atom probe tomography, and ex situ measurements of Small-Angle Neutron Scattering (SANS). The advantage of SANS over the other two characterization techniques is that SANS allows...
journal article 2020
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Bakker, J.H. (author), Washington, Adam L. (author), Parnell, S.R. (author), van Well, A.A. (author), Pappas, C. (author), Bouwman, W.G. (author)
SESANS data analysis has been implemented in the SasView software package, allowing SESANS experiments to be analyzed using a numerical Hankel transformation of isotropic small-angle scattering (SAS) models. The error of the numerical approximation is three orders of magnitude below typical experimental errors. All advanced data fitting...
journal article 2020
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Ioannidou, C. (author), Navarro Lopez, A. (author), Rijkenberg, Arjan (author), Dalgliesh, Robert M. (author), Koelling, Sebastian (author), Pappas, C. (author), Sietsma, J. (author), van Well, A.A. (author), Offerman, S.E. (author)
In-situ Small-Angle Neutron Scattering (SANS) is used to determine the time evolution of the chemical composition of precipitates at 650 °C and 700 °C in three micro-alloyed steels with different vanadium (V) and carbon (C) concentrations. Precipitates with a distribution of substoichiometric carbon-to-metal ratios are measured in all steels....
journal article 2020
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Ioannidou, C. (author), Arechabaleta Guenechea, Z. (author), Navarro Lopez, A. (author), Rijkenberg, Arjan (author), Dalgliesh, Robert M. (author), Kölling, S. (author), Bliznuk, Vitaliy (author), Pappas, C. (author), Sietsma, J. (author), van Well, A.A. (author), Offerman, S.E. (author)
The precipitation kinetics of vanadium carbides and its interaction with the austenite-to-ferrite phase transformation is studied in two micro-alloyed steels that differ in vanadium and carbon concentrations by a factor of two, but have the same vanadium-to-carbon atomic ratio of 1:1. Dilatometry is used for heat-treating the specimens and...
journal article 2019
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Bannenberg, L.J. (author), Wilhelm, Heribert (author), Cubitt, Robert (author), Labh, A. (author), Schmidt, Marcus P. (author), Lelievre-Berna, Eddy (author), Pappas, C. (author), Mostovoy, Maxim (author), Leonov, Andrey O. (author)
Magnetic skyrmions are topologically protected nanoscale spin textures with particle-like properties. In bulk cubic helimagnets, they appear under applied magnetic fields and condense spontaneously into a lattice in a narrow region of the phase diagram just below the magnetic ordering temperature, the so-called A-phase. Theory, however, predicts...
journal article 2019
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Leonov, A.O. (author), Pappas, C. (author)
Recent experimental findings in the bulk cubic helimagnet and Mott insulator Cu2OSeO3 highlight the paramount role of cubic anisotropy in stabilizing novel chiral and skyrmion phases. It was indeed found that if a magnetic field is applied along the easy 001 crystallographic direction, competing cubic and<br/>exchange anisotropies tilt the wave...
journal article 2019
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Bannenberg, L.J. (author), Sadykov, R. (author), Dalgliesh, R. M. (author), Goodway, C. (author), Schlagel, D. L. (author), Lograsso, T. A. (author), Falus, P. (author), Lelièvre-Berna, E. (author), Pappas, C. (author)
The archetype cubic chiral magnet MnSi is home to some of the most fascinating states in condensed matter, such as skyrmions and a non-Fermi-liquid behavior in conjunction with a topological Hall effect under hydrostatic pressure. Using small angle neutron scattering, we study the evolution of the helimagnetic, conical, and skyrmionic...
journal article 2019
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Tian, B. (author), Garcia Sakai, Victoria (author), Pappas, C. (author), van der Goot, Atze Jan (author), Bouwman, W.G. (author)
We present an investigation of the dynamics of calcium caseinate as a function of hydration, solvent isotope (H<sub>2</sub>O and D<sub>2</sub>O) and drying methods (roller drying and spray drying), using quasi-elastic neutron scattering (QENS). These factors are key to the formation of fibres in this material which makes it a potential...
journal article 2019
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Mirebeau, I. (author), Martin, N (author), Deutsch, M. (author), Bannenberg, L.J. (author), Pappas, C. (author), Chaboussant, G. (author), Cubitt, R (author), Decorse, C. (author), Leonov, A.O. (author)
journal article 2018
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Sadykov, Ravil (author), Pappas, C. (author), Bannenberg, L.J. (author), Dalgliesh, Robert M. (author), Falus, Péter (author), Goodway, Christopher (author), Lelièvre-Berna, Eddy (author)
We have developed and realised a compact high-pressure clamp cell of the piston-cylinder type for Small Angle Neutron Scattering (SANS) and Neutron Spin Echo (NSE) spectroscopy measurements. The cell can pressurise φ5 mm samples up to 1.5 GPa. It is non-magnetic, produces a sufficiently low and flat SANS background with a relatively good...
journal article 2018
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Qian, F. (author), Bannenberg, L.J. (author), Wilhelm, Heribert (author), Chaboussant, Grégory (author), Debeer-Schmitt, Lisa M. (author), Schmidt, Marcus P. (author), Aqeel, Aisha (author), Palstra, Thomas T.M. (author), Brück, E.H. (author), Lefering, A.J.E. (author), Pappas, C. (author), Mostovoy, Maxim (author), Leonov, Andrey O. (author)
The lack of inversion symmetry in the crystal lattice of magnetic materials gives rise to complex noncollinear spin orders through interactions of a relativistic nature, resulting in interesting physical phenomena, such as emergent electromagnetism. Studies of cubic chiral magnets revealed a universal magnetic phase diagram composed of...
journal article 2018
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Bannenberg, L.J. (author), Qian, F. (author), Dalgliesh, R. M. (author), Martin, N (author), Chaboussant, G. (author), Schmidt, M (author), Schlagel, D. L. (author), Lograsso, T. A. (author), Wilhelm, H (author), Pappas, C. (author)
Magnetic skyrmions are nanosized topologically protected spin textures with particlelike properties. They can form lattices perpendicular to the magnetic field, and the orientation of these skyrmion lattices with respect to the crystallographic lattice is governed by spin-orbit coupling. By performing small-angle neutron scattering measurements,...
journal article 2017
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Bannenberg, L.J. (author), Kakurai, K. (author), Falus, P. (author), Lelievre-Berna, E. (author), Dalgliesh, R. (author), Dewhurst, C.D. (author), Qian, F. (author), Onose, Y. (author), Endoh, Y. (author), Tokura, Y. (author), Pappas, C. (author)
We present a comprehensive Small Angle Neutron Scattering (SANS) and Neutron Spin Echo Spectroscopy (NSE) study of the structural and dynamical aspects of the helimagnetic transition in Fe<sub>1-x</sub>Co<sub>x</sub>Si with x = 0.30. In contrast to the sharp transition observed in the archetype chiral magnet MnSi, the transition in Fe<sub>1-x<...
journal article 2017
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Pappas, C. (author), Bannenberg, L.J. (author), Lelièvre-Berna, E. (author), Qian, F. (author), Dewhurst, C. D. (author), Dalgliesh, R. M. (author), Schlagel, D. L. (author), Lograsso, T. A. (author), Falus, P (author)
The reference chiral helimagnet MnSi is the first system where Skyrmion lattice correlations have been reported. At a zero magnetic field the transition at TC to the helimagnetic state is of first order. Above TC, in a region dominated by precursor phenomena, neutron scattering shows the buildup of strong chiral fluctuating correlations over...
journal article 2017
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Bannenberg, L.J. (author), Lefering, A.J.E. (author), Kakurai, K. (author), Onose, Y (author), Endoh, Y. (author), Tokura, Y (author), Pappas, C. (author)
We present a systematic study of the ac susceptibility of the chiral magnet Fe1−xCoxSi with x=0.30 covering four orders of magnitude in frequencies from 0.1 Hz to 1 kHz, with particular emphasis to the pronounced history dependence. Characteristic relaxation times ranging from a few milliseconds to tens of seconds are observed around the...
journal article 2016
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Rodriguez, D. Martin (author), Bentley, P. M. (author), Pappas, C. (author)
Polarised neutron beams are used in disciplines as diverse as magnetism,soft matter or biology. However, most of these applications often suffer from low flux also because the existing neutron polarising methods imply the filtering of one of the spin states, with a transmission of 50% at maximum. With the purpose of using all neutrons that...
journal article 2016
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Bannenberg, L.J. (author), Kakurai, K. (author), Qian, F. (author), Lelièvre-Berna, E. (author), Dewhurst, C. D. (author), Onose, Y. (author), Endoh, Y. (author), Tokura, Y (author), Pappas, C. (author)
Small angle neutron scattering measurements on a bulk single crystal of the doped chiral magnet Fe1-xCoxSi with x=0.3 reveal a pronounced effect of the magnetic history and cooling rates on the magnetic phase diagram. The extracted phase diagrams are qualitatively different for zero and field cooling and reveal a metastable skyrmion lattice...
journal article 2016
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van Eijck, L. (author), Cussen, L. D. (author), Sykora, G. J. (author), Schooneveld, E. M. (author), Rhodes, N. J. (author), van Well, A.A. (author), Pappas, C. (author)
The performance of the new neutron powder diffraction instrument PEARL that is installed at the research reactor of Delft University of Technology is reported. It is based on the optimization concepts developed by Cussen [Nucl. Instrum. Methods Phys. Res. Sect. A (2007), 583, 394-406], which lead to high performance competing with existing...
journal article 2016
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Qian, F. (author), Wilhelm, H. (author), Aqeel, A. (author), Palstra, T.T.M. (author), Lefering, A.J.E. (author), Brück, E.H. (author), Pappas, C. (author)
We present an investigation of the magnetic-field-temperature phase diagram of Cu2OSeO3 based on dc magnetization and ac susceptibility measurements covering a broad frequency range of four orders of magnitude, from very low frequencies reaching 0.1 Hz up to 1 kHz. The experiments were performed in the vicinity of Tc=58.2 K and around the...
journal article 2016
Searched for: author:"Pappas, C."
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