Search

Your search keyword '"Mawass, Mohamad-Assaad"' showing total 44 results
Start Over Author "Mawass, Mohamad-Assaad"
44 results on '"Mawass, Mohamad-Assaad"'

2. Role of substrate clamping on anisotropy and domain structure in the canted antiferromagnet $\alpha$-Fe$_2$O$_3$

Author

Wittmann, Angela, Gomonay, Olena, Litzius, Kai, Kaczmarek, Allison, Kossak, Alexander E., Wolf, Daniel, Lubk, Axel, Johnson, Tyler N., Tremsina, Elizaveta A., Churikova, Alexandra, Büttner, Felix, Wintz, Sebastian, Mawass, Mohamad-Assaad, Weigand, Markus, Kronast, Florian, Scipioni, Larry, Shepard, Adam, Newhouse-Illig, Ty, Greer, James A, Schütz, Gisela, Birge, Norman O., and Beach, Geoffrey S. D.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Materials Science
Abstract

Antiferromagnets have recently been propelled to the forefront of spintronics by their high potential for revolutionizing memory technologies. For this, understanding the formation and driving mechanisms of the domain structure is paramount. In this work, we investigate the domain structure in a thin-film canted antiferromagnet $\alpha$-Fe$_2$O$_3$. We find that the internal destressing fields driving the formation of domains do not follow the crystal symmetry of $\alpha$-Fe$_2$O$_3$, but fluctuate due to substrate clamping. This leads to an overall isotropic distribution of the N\'eel order with locally varying effective anisotropy in antiferromagnetic thin films. Furthermore, we show that the weak ferromagnetic nature of $\alpha$-Fe$_2$O$_3$ leads to a qualitatively different dependence on magnetic field compared to collinear antiferromagnets such as NiO. The insights gained from our work serve as a foundation for further studies of electrical and optical manipulation of the domain structure of antiferromagnetic thin films., Comment: 9 pages, 5 figures

Published
2022
Full Text
View/download PDF

3. Strain-induced Shape Anisotropy in Antiferromagnetic Structures

Author

Meer, Hendrik, Gomonay, Olena, Schmitt, Christin, Ramos, Rafael, Schnitzspan, Leo, Kronast, Florian, Mawass, Mohamad-Assaad, Valencia, Sergio, Saitoh, Eiji, Sinova, Jairo, Baldrati, Lorenzo, and Kläui, Mathias

Subjects
Condensed Matter - Materials Science
Abstract

We demonstrate how shape-induced strain can be used to control antiferromagnetic order in NiO/Pt thin films. For rectangular elements patterned along the easy and hard magnetocrystalline anisotropy axes of our film, we observe different domain structures and we identify magnetoelastic interactions that are distinct for different domain configurations. We reproduce the experimental observations by modeling the magnetoelastic interactions, considering spontaneous strain induced by the domain configuration, as well as elastic strain due to the substrate and the shape of the patterns. This allows us to demonstrate and explain how the variation of the aspect ratio of rectangular elements can be used to control the antiferromagnetic ground state domain configuration. Shape-dependent strain does not only need to be considered in the design of antiferromagnetic devices, but can potentially be used to tailor their properties, providing an additional handle to control antiferromagnets.

Published
2022
Full Text
View/download PDF

4. Skyrmions in synthetic antiferromagnets and their nucleation via electrical current and ultrafast laser illumination

Author

Juge, Roméo, Sisodia, Naveen, Larrañaga, Joseba Urrestarazu, Zhang, Qiang, Pham, Van Tuong, Rana, Kumari Gaurav, Sarpi, Brice, Mille, Nicolas, Stanescu, Stefan, Belkhou, Rachid, Mawass, Mohamad-Assaad, Novakovic-Marinkovic, Nina, Kronast, Florian, Weigand, Markus, Gräfe, Joachim, Wintz, Sebastian, Finizio, Simone, Raabe, Jörg, Aballe, Lucia, Foerster, Michael, Belmeguenai, Mohamed, Buda-Prejbeanu, Liliana, Shaw, Justin M., Nembach, Hans T., Ranno, Laurent, Gaudin, Gilles, and Boulle, Olivier

Subjects
Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Magnetic skyrmions are topological spin textures that hold great promise as nanoscale information carriers in non-volatile memory and logic devices. While room-temperature magnetic skyrmions and their current-induced manipulation were recently demonstrated, the stray field resulting from their finite magnetization as well as their topological charge limit their minimum size and reliable motion in tracks. Antiferromagnetic (AF) skyrmions allow these limitations to be lifted owing to their vanishing magnetization and net zero topological charge, promising room-temperature, ultrasmall skyrmions, fast dynamics, and insensitivity to external magnetic fields. While room-temperature AF spin textures have been recently demonstrated, the observation and controlled nucleation of AF skyrmions operable at room temperature in industry-compatible synthetic antiferromagnetic (SAF) material systems is still lacking. Here we demonstrate that isolated skyrmions can be stabilized at zero field and room temperature in a fully compensated SAF. Using X-ray microscopy techniques, we are able to observe the skyrmions in the different SAF layers and demonstrate their antiparallel alignment. The results are substantiated by micromagnetic simulations and analytical models using experimental parameters, which confirm the chiral SAF skyrmion spin texture and allow the identification of the physical mechanisms that control the SAF skyrmion size and stability. We also demonstrate the local nucleation of SAF skyrmions via local current injection as well as ultrafast laser excitations at zero field. These results will enable the utilization of SAF skyrmions in skyrmion-based devices.

Published
2021
Full Text
View/download PDF

5. Growth and regrowth of adult sea urchin spines involve hydrated and anhydrous amorphous calcium carbonate precursors

Author

Albéric, Marie, Stifler, Cayla A, Zou, Zhaoyong, Sun, Chang-Yu, Killian, Christopher E, Valencia, Sergio, Mawass, Mohamad-Assaad, Bertinetti, Luca, Gilbert, Pupa UPA, and Politi, Yael

Subjects
Biochemistry and Cell Biology, Biological Sciences, Life Below Water, Sea urchin spine regeneration, Anhydrous amorphous calcium carbonate, Hydrated amorphous calcium carbonate, Ca L-2, L-3-edge spectra, PhotoEmission Electron spectroMicroscopy, Ca L2, 3-edge spectra, Biochemistry and cell biology
Abstract

In various mineralizing marine organisms, calcite or aragonite crystals form through the initial deposition of amorphous calcium carbonate (ACC) phases with different hydration levels. Using X-ray PhotoEmission Electron spectroMicroscopy (X-PEEM), ACCs with varied spectroscopic signatures were previously identified. In particular, ACC type I and II were recognized in embryonic sea urchin spicules. ACC type I was assigned to hydrated ACC based on spectral similarity with synthetic hydrated ACC. However, the identity of ACC type II has never been unequivocally determined experimentally. In the present study we show that synthetic anhydrous ACC and ACC type II identified here in sea urchin spines, have similar Ca L 2,3-edge spectra. Moreover, using X-PEEM chemical mapping, we revealed the presence of ACC-H2O and anhydrous ACC in growing stereom and septa regions of sea urchin spines, supporting their role as precursor phases in both structures. However, the distribution and the abundance of the two ACC phases differ substantially between the two growing structures, suggesting a variation in the crystal growth mechanism; in particular, ACC dehydration, in the two-step reaction ACC-H2O → ACC → calcite, presents different kinetics, which are proposed to be controlled biologically.

Published
2019

6. Time-resolved imaging of pulse-induced magnetization reversal with a microwave assist field

Author

Rao, Siddharth, Rhensius, Jan, Bisig, Andre, Mawass, Mohamad-Assaad, Weigand, Markus, Klaui, Mathias, Bhatia, Charanjit S., and Yang, Hyunsoo

Subjects
Condensed Matter - Materials Science
Abstract

The reversal of the magnetization under the influence of a field pulse has been previously predicted to be an incoherent process with several competing phenomena such as domain wall relaxation, spin wave-mediated instability regions, and vortex-core mediated reversal dynamics. However, there has been no study on the direct observation of the switching process with the aid of a microwave signal input. We report a time-resolved imaging study of magnetization reversal in patterned magnetic structures under the influence of a field pulse with microwave assistance. The microwave frequency is varied to demonstrate the effect of resonant microwave-assisted switching. We observe that the switching process is dominated by spin wave dynamics generated as a result of magnetic instabilities in the structures, and identify the frequencies that are most dominant in magnetization reversal.

Published
2015

8. Size-Dependence and High Temperature Stability of Radial Vortex Magnetic Textures Imprinted by Superconductor Stray Fields

Author

Sanchez-Manzano, David, primary, Orfila, Gloria, additional, Sander, Anke, additional, Marcano, Lourdes, additional, Gallego, Fernando, additional, Mawass, Mohamad-Assaad, additional, Grilli, Francesco, additional, Arora, Ashima, additional, Peralta, Andrea, additional, Cuellar, Fabian A., additional, Fernandez-Roldan, Jose A., additional, Reyren, Nicolas, additional, Kronast, Florian, additional, Leon, Carlos, additional, Rivera-Calzada, Alberto, additional, Villegas, Javier E., additional, Santamaria, Jacobo, additional, and Valencia, Sergio, additional

Published
2024
Full Text
View/download PDF

9. Observation of room-temperature magnetic skyrmions and their current-driven dynamics in ultrathin metallic ferromagnets

Author

Woo, Seonghoon, Litzius, Kai, Krüger, Benjamin, Im, Mi-Young, Caretta, Lucas, Richter, Kornel, Mann, Maxwell, Krone, Andrea, Reeve, Robert M, Weigand, Markus, Agrawal, Parnika, Lemesh, Ivan, Mawass, Mohamad-Assaad, Fischer, Peter, Kläui, Mathias, and Beach, Geoffrey SD

Subjects
Quantum Physics, Physical Sciences, cond-mat.mtrl-sci, Nanoscience & Nanotechnology
Abstract

Magnetic skyrmions are topologically protected spin textures that exhibit fascinating physical behaviours and large potential in highly energy-efficient spintronic device applications. The main obstacles so far are that skyrmions have been observed in only a few exotic materials and at low temperatures, and fast current-driven motion of individual skyrmions has not yet been achieved. Here, we report the observation of stable magnetic skyrmions at room temperature in ultrathin transition metal ferromagnets with magnetic transmission soft X-ray microscopy. We demonstrate the ability to generate stable skyrmion lattices and drive trains of individual skyrmions by short current pulses along a magnetic racetrack at speeds exceeding 100 m s(-1) as required for applications. Our findings provide experimental evidence of recent predictions and open the door to room-temperature skyrmion spintronics in robust thin-film heterostructures.

Published
2016

10. Size-dependence and high temperature stability of radial vortex magnetic textures imprinted by superconductor stray fields

Author

Sánchez Manzano, David, Orfila Rodríguez, Gloria, Sander, Anke, Marcano, Lourdes, Gallego Toledo, Fernando, Mawass, Mohamad-Assaad, Grilli, Francesco, Arora, Ashima, Peralta, Andrea, Cuéllar Jiménez, Fabian Andrés, Fernández Roldán, Jose A., Reyren, NIcolas, Kronast, Florian, León Yebra, Carlos, Rivera Calzada, Alberto Carlos, Villegas, Javier E, Santamaría Sánchez-Barriga, Jacobo, Valencia, Sergio, Sánchez Manzano, David, Orfila Rodríguez, Gloria, Sander, Anke, Marcano, Lourdes, Gallego Toledo, Fernando, Mawass, Mohamad-Assaad, Grilli, Francesco, Arora, Ashima, Peralta, Andrea, Cuéllar Jiménez, Fabian Andrés, Fernández Roldán, Jose A., Reyren, NIcolas, Kronast, Florian, León Yebra, Carlos, Rivera Calzada, Alberto Carlos, Villegas, Javier E, Santamaría Sánchez-Barriga, Jacobo, and Valencia, Sergio

Abstract

Swirling spin textures, including topologically nontrivial states, such as skyrmions, chiral domain walls, and magnetic vortices, have garnered significant attention within the scientific community due to their appeal from both fundamental and applied points of view. However, their creation, controlled manipulation, and stability are typically constrained to certain systems with specific crystallographic symmetries, bulk or interface interactions, and/or a precise stacking sequence of materials. Recently, a new approach has shown potential for the imprint of magnetic radial vortices in soft ferromagnetic compounds making use of the stray field of YBa2Cu3O7-delta superconducting microstructures in ferromagnet/superconductor (FM/SC) hybrids at temperatures below the superconducting transition temperature (T-C). Here, we explore the lower size limit for the imprint of magnetic radial vortices in square and disc shaped structures as well as the persistence of these spin textures above T-C, with magnetic domains retaining partial memory. Structures with circular geometry and with FM patterned to smaller radius than the superconductor island facilitate the imprinting of magnetic radial vortices and improve their stability above T-C, in contrast to square structures where the presence of magnetic domains increases the dipolar energy. Micromagnetic modeling coupled with a SC field model reveals that the stabilization mechanism above T-C is mediated by microstructural defects. Superconducting control of swirling spin textures, and their stabilization above the superconducting transition temperature by means of defect engineering holds promising prospects for shaping superconducting spintronics based on magnetic textures, Helmholtz Zentrum Berlin fur Materialen und Energie, European Commission, MInisterio de Economía y Competitividad (España), Agence Nationale de la Recherche (France), Alexander von Humboldt Foundation, Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub, Pagado por el autor

Published
2024

13. Strain‐Modulated Ferromagnetism at an Intrinsic van der Waals Heterojunction

Author

Fujita, Ryuji, primary, Gurung, Gautam, additional, Mawass, Mohamad‐Assaad, additional, Smekhova, Alevtina, additional, Kronast, Florian, additional, Toh, Alexander Kang‐Jun, additional, Soumyanarayanan, Anjan, additional, Ho, Pin, additional, Singh, Angadjit, additional, Heppell, Emily, additional, Backes, Dirk, additional, Maccherozzi, Francesco, additional, Watanabe, Kenji, additional, Taniguchi, Takashi, additional, Mayoh, Daniel A., additional, Balakrishnan, Geetha, additional, van der Laan, Gerrit, additional, and Hesjedal, Thorsten, additional

Published
2024
Full Text
View/download PDF

14. Role of substrate clamping on anisotropy and domain structure in the canted antiferromagnet α-Fe2O3

Author

Wittmann, Angela, Gomonay, Olena, Litzius, Kai, Kaczmarek, Allison, Kossak, Alexander E., Wolf, Daniel, Lubk, Axel, Johnson, Tyler N., Tremsina, Elizaveta A., Churikova, Alexandra, Büttner, Felix, Wintz, Sebastian, Mawass, Mohamad-Assaad, Weigand, Markus, Kronast, Florian, Scipioni, Larry, Shepard, Adam, Newhouse-Illig, Ty, Greer, James A, Schütz, Gisela, Birge, Norman O., and Beach, Geoffrey S. D.

Subjects
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences
Abstract

Antiferromagnets have recently been propelled to the forefront of spintronics by their high potential for revolutionizing memory technologies. For this, understanding the formation and driving mechanisms of the domain structure is paramount. In this work, we investigate the domain structure in a thin-film canted antiferromagnet $α$-Fe$_2$O$_3$. We find that the internal destressing fields driving the formation of domains do not follow the crystal symmetry of $α$-Fe$_2$O$_3$, but fluctuate due to substrate clamping. This leads to an overall isotropic distribution of the Néel order with locally varying effective anisotropy in antiferromagnetic thin films. Furthermore, we show that the weak ferromagnetic nature of $α$-Fe$_2$O$_3$ leads to a qualitatively different dependence on magnetic field compared to collinear antiferromagnets such as NiO. The insights gained from our work serve as a foundation for further studies of electrical and optical manipulation of the domain structure of antiferromagnetic thin films., 9 pages, 5 figures

Published
2022

15. Role of substrate clamping on anisotropy and domain structure in the canted antiferromagnet α−Fe2O3

Author

Wittmann, Angela, primary, Gomonay, Olena, additional, Litzius, Kai, additional, Kaczmarek, Allison, additional, Kossak, Alexander E., additional, Wolf, Daniel, additional, Lubk, Axel, additional, Johnson, Tyler N., additional, Tremsina, Elizaveta A., additional, Churikova, Alexandra, additional, Büttner, Felix, additional, Wintz, Sebastian, additional, Mawass, Mohamad-Assaad, additional, Weigand, Markus, additional, Kronast, Florian, additional, Scipioni, Larry, additional, Shepard, Adam, additional, Newhouse-Illige, Ty, additional, Greer, James A., additional, Schütz, Gisela, additional, Birge, Norman O., additional, and Beach, Geoffrey S. D., additional

Published
2022
Full Text
View/download PDF

16. Strain-induced shape anisotropy in antiferromagnetic structures

Author

Meer, Hendrik, primary, Gomonay, Olena, additional, Schmitt, Christin, additional, Ramos, Rafael, additional, Schnitzspan, Leo, additional, Kronast, Florian, additional, Mawass, Mohamad-Assaad, additional, Valencia, Sergio, additional, Saitoh, Eiji, additional, Sinova, Jairo, additional, Baldrati, Lorenzo, additional, and Kläui, Mathias, additional

Published
2022
Full Text
View/download PDF

17. Skyrmions in synthetic antiferromagnets and their nucleation via electrical current and ultra-fast laser illumination

Author

Juge, Roméo, primary, Sisodia, Naveen, additional, Larrañaga, Joseba Urrestarazu, additional, Zhang, Qiang, additional, Pham, Van Tuong, additional, Rana, Kumari Gaurav, additional, Sarpi, Brice, additional, Mille, Nicolas, additional, Stanescu, Stefan, additional, Belkhou, Rachid, additional, Mawass, Mohamad-Assaad, additional, Novakovic-Marinkovic, Nina, additional, Kronast, Florian, additional, Weigand, Markus, additional, Gräfe, Joachim, additional, Wintz, Sebastian, additional, Finizio, Simone, additional, Raabe, Jörg, additional, Aballe, Lucia, additional, Foerster, Michael, additional, Belmeguenai, Mohamed, additional, Buda-Prejbeanu, Liliana D., additional, Pelloux-Prayer, Johan, additional, Shaw, Justin M., additional, Nembach, Hans T., additional, Ranno, Laurent, additional, Gaudin, Gilles, additional, and Boulle, Olivier, additional

Published
2022
Full Text
View/download PDF

18. Strain tuning of Néel temperature in YCrO3 epitaxial thin films

Author

Lee, Jin Hong, primary, Marcano, Lourdes, additional, Aeschlimann, Raphaël, additional, Mawass, Mohamad-Assaad, additional, Luo, Chen, additional, Gloter, Alexandre, additional, Varignon, Julien, additional, Radu, Florin, additional, Valencia, Sergio, additional, and Bibes, Manuel, additional

Published
2022
Full Text
View/download PDF

20. Strain tuning of Néel temperature in YCrO3 epitaxial thin films.

Author

Lee, Jin Hong, Marcano, Lourdes, Aeschlimann, Raphaël, Mawass, Mohamad-Assaad, Luo, Chen, Gloter, Alexandre, Varignon, Julien, Radu, Florin, Valencia, Sergio, and Bibes, Manuel

Subjects
PULSED laser deposition, THIN films, DENSITY functional theory, CHEMICAL bond lengths, PEROVSKITE, TEMPERATURE
Abstract

Epitaxial strain is a useful handle to engineer the physical properties of perovskite oxide materials. Here, we apply it to orthorhombic chromites that are a family of antiferromagnets showing fruitful functionalities as well as strong spin–lattice coupling via antisymmetric exchange interaction along Cr–O–Cr bonds. Using pulsed laser deposition, we grow YCrO3 thin films on various substrates imposing strain levels in the range from −1.8% to +0.3%. The films are stoichiometric with a 3+ valence for Cr both within the films and at their surface. They display an antiferromagnetic spin order below their Néel temperature, which we show can be strongly tuned by epitaxial strain with a slope of −8.54 K/%. A dimensionless figure of merit (defined as the slope normalized by the Néel temperature of bulk) is determined to be 6.1, which is larger than that of other perovskites, such as manganites (5.5), ferrites (2.3), or nickelates (4.6). Density functional theory simulations bring insight into the role of Cr–O bond lengths and oxygen octahedral rotations on the observed behavior. Our results shed light on orthorhombic chromites that may offer an energy-efficient piezo-spintronic operation. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

21. Domain-Wall Damping in Ultrathin Nanostripes with Dzyaloshinskii-Moriya Interaction

Author

Volkov, Oleksii M., primary, Kronast, Florian, additional, Abert, Claas, additional, Mata, Eduardo Sergio Oliveros, additional, Kosub, Tobias, additional, Makushko, Pavlo, additional, Erb, Denise, additional, Pylypovskyi, Oleksandr V., additional, Mawass, Mohamad-Assaad, additional, Sheka, Denis, additional, Zhou, Shengqiang, additional, Fassbender, Jürgen, additional, and Makarov, Denys, additional

Published
2021
Full Text
View/download PDF

26. Scaling of intrinsic domain wall magnetoresistance with confinement in electromigrated nanocontacts

Author

Reeve, Robert M., primary, Loescher, André, additional, Kazemi, Hamidreza, additional, Dupé, Bertrand, additional, Mawass, Mohamad-Assaad, additional, Winkler, Thomas, additional, Schönke, Daniel, additional, Miao, Jun, additional, Litzius, Kai, additional, Sedlmayr, Nicholas, additional, Schneider, Imke, additional, Sinova, Jairo, additional, Eggert, Sebastian, additional, and Kläui, Mathias, additional

Published
2019
Full Text
View/download PDF

30. Observation of room-temperature magnetic skyrmions and their current-driven dynamics in ultrathin metallic ferromagnets

Author

Massachusetts Institute of Technology. Department of Materials Science and Engineering, Woo, Seonghoon, Caretta, Lucas Marcelo, Mann, Maxwell, Agrawal, Parnika, Beach, Geoffrey Stephen, Litzius, Kai, Krüger, Benjamin, Im, Mi-Young, Richter, Kornel, Krone, Andrea, Reeve, Robert M., Weigand, Markus, Lemesh, Ivan, Mawass, Mohamad-Assaad, Fischer, Peter, Kläui, Mathias, Massachusetts Institute of Technology. Department of Materials Science and Engineering, Woo, Seonghoon, Caretta, Lucas Marcelo, Mann, Maxwell, Agrawal, Parnika, Beach, Geoffrey Stephen, Litzius, Kai, Krüger, Benjamin, Im, Mi-Young, Richter, Kornel, Krone, Andrea, Reeve, Robert M., Weigand, Markus, Lemesh, Ivan, Mawass, Mohamad-Assaad, Fischer, Peter, and Kläui, Mathias

Abstract

Magnetic skyrmions are topologically protected spin textures that exhibit fascinating physical behaviours and large potential in highly energy-efficient spintronic device applications. The main obstacles so far are that skyrmions have been observed in only a few exotic materials and at low temperatures, and fast current-driven motion of individual skyrmions has not yet been achieved. Here, we report the observation of stable magnetic skyrmions at room temperature in ultrathin transition metal ferromagnets with magnetic transmission soft X-ray microscopy. We demonstrate the ability to generate stable skyrmion lattices and drive trains of individual skyrmions by short current pulses along a magnetic racetrack at speeds exceeding 100 m s-1as required for applications. Our findings provide experimental evidence of recent predictions and open the door to room-temperature skyrmion spintronics in robust thin-film heterostructures., United States. Department of Energy. Office of Basic Energy Sciences (Award DE-SC0012371)

Published
2018

33. Switching by Domain-Wall Automotion in Asymmetric Ferromagnetic Rings

Author

Mawass, Mohamad-Assaad, primary, Richter, Kornel, additional, Bisig, Andre, additional, Reeve, Robert M., additional, Krüger, Benjamin, additional, Weigand, Markus, additional, Stoll, Hermann, additional, Krone, Andrea, additional, Kronast, Florian, additional, Schütz, Gisela, additional, and Kläui, Mathias, additional

Published
2017
Full Text
View/download PDF

36. Correlation between spin structure oscillations and domain wall velocities

Author

Bisig, Andre, Staerk, Martin, Mawass, Mohamad-assaad, Moutafis, Christoforos, Rhensius, Jan, Heidler, Jakoba, Buettner, Felix, Noske, Matthias, Weigand, Markus, Eisebitt, Stefan, Tyliszczak, Tolek, Waeyenberge, Bartel, Stoll, Hermann, Schuetz, Gisela, Klaeui, Mathias, Bisig, Andre, Staerk, Martin, Mawass, Mohamad-assaad, Moutafis, Christoforos, Rhensius, Jan, Heidler, Jakoba, Buettner, Felix, Noske, Matthias, Weigand, Markus, Eisebitt, Stefan, Tyliszczak, Tolek, Waeyenberge, Bartel, Stoll, Hermann, Schuetz, Gisela, Klaeui, and Mathias

Published
2013

37. Enhancement of Ti3C2MXene Pseudocapacitance after Urea Intercalation Studied by Soft X-ray Absorption Spectroscopy

Author

Al-Temimy, Ameer, Anasori, Babak, Mazzio, Katherine A., Kronast, Florian, Seredych, Mykola, Kurra, Narendra, Mawass, Mohamad-Assaad, Raoux, Simone, Gogotsi, Yury, and Petit, Tristan

Abstract

MXenes have shown outstanding properties due to their highly active hydrophilic surfaces coupled with high metallic conductivity. Many applications rely on the intercalation between Ti3C2Tx(Txdescribes the -OH, -F and -O- surface terminations) flakes by ions or molecules, which in turn might alter the Ti3C2Txsurface chemistry and electrochemical properties. In this work, we show that the capacitance, rate capability, and charge carrier kinetics in Ti3C2TxMXene electrodes are remarkably enhanced after urea intercalation (u-Ti3C2Tx). In particular, the areal capacitance increased to 1100 mF/cm2, which is 56% higher than that of pristine Ti3C2Txelectrodes. We attribute this dramatic improvement to changes in the Ti3C2Txsurface chemistry upon urea intercalation. The oxidation state and the oxygen bonding of individual Ti3C2Txflakes before and after urea intercalation are probed by soft X-ray absorption spectroscopy (XAS) at the Ti L- and O K-edges with 30 nm spatial resolution in vacuum. After urea intercalation, a higher Ti oxidation state is observed across the entire flake compared to pristine Ti3C2Tx. Additionally, in situ XAS of u-Ti3C2Txaqueous dispersions reveal a higher Ti oxidation similar to dry samples, while for pristine Ti3C2Txthe Ti atoms are significantly reduced in water compared to dry samples.

Published
2020
Full Text
View/download PDF

40. Dynamic domain wall chirality rectification by rotating magnetic fields

Author

Bisig, Andre, primary, Mawass, Mohamad-Assaad, additional, Stärk, Martin, additional, Moutafis, Christoforos, additional, Rhensius, Jan, additional, Heidler, Jakoba, additional, Gliga, Sebastian, additional, Weigand, Markus, additional, Tyliszczak, Tolek, additional, Van Waeyenberge, Bartel, additional, Stoll, Hermann, additional, Schütz, Gisela, additional, and Kläui, Mathias, additional

Published
2015
Full Text
View/download PDF

42. Correlation between spin structure oscillations and domain wall velocities (presentation video)

Author

Bisig, Andre, additional, Stärk, Martin, additional, Mawass, Mohamad-Assaad, additional, Moutafis, Christoforos, additional, Rhensius, Jan, additional, Heidler, Jakoba, additional, Büttner, Felix, additional, Noske, Matthias, additional, Weigand, Markus, additional, Eisebitt, Stefan, additional, Tyliszczak, Tolek, additional, van Waeyenberge, Bartel, additional, Stoll, Hermann, additional, Schütz, Gisela, additional, and Kläui, Mathias, additional

Published
2014
Full Text
View/download PDF

43. Dynamics and topological mass of skyrmionic spin structures (presentation video)

Author

Moutafis, Christoforos, additional, Büttner, Felix, additional, Bisig, Andre, additional, Krüger, Benjamin, additional, Vaz, C. A. F., additional, Foerster, Michael, additional, Mawass, Mohamad-Assaad, additional, Schneider, Michael, additional, Gunther, Christian, additional, Geilhufe, Jan, additional, von Korff Schmising, C., additional, Mohanty, J., additional, Pfau, B., additional, Schaffert, Stefan, additional, Schulz, Tomek, additional, Weigand, Markus, additional, Swagten, Henk J. M., additional, Raabe, Jörg, additional, Kläui, Mathias, additional, and Eisebitt, Stefan, additional

Published
2014
Full Text
View/download PDF

44. Synchronous precessional motion of multiple domain walls in a ferromagnetic nanowire by perpendicular field pulses

Author

Kim, June-Seo, primary, Mawass, Mohamad-Assaad, additional, Bisig, André, additional, Krüger, Benjamin, additional, Reeve, Robert M., additional, Schulz, Tomek, additional, Büttner, Felix, additional, Yoon, Jungbum, additional, You, Chun-Yeol, additional, Weigand, Markus, additional, Stoll, Hermann, additional, Schütz, Gisela, additional, Swagten, Henk J. M., additional, Koopmans, Bert, additional, Eisebitt, Stefan, additional, and Kläui, Mathias, additional

Published
2014
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results