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Your search keyword '"Cascales Sandoval, Miguel A."' showing total 14 results
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14 results on '"Cascales Sandoval, Miguel A."'

1. Determination of optimal experimental conditions for accurate 3D reconstruction of the magnetization vector via XMCD-PEEM

Author

Engineering and Physical Sciences Research Council (UK), European Commission, Gobierno de Aragón, Agencia Estatal de Investigación (España), Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Ciencia e Innovación (España), Fundación para el Fomento en Asturias de la Investigación Científica Aplicada y la Tecnología, Alexander von Humboldt Foundation, Max Planck Society, Generalitat de Catalunya, Projekt DEAL, Cascales Sandoval, Miguel A., Hierro-Rodríguez, Aurelio, Ruiz-Gómez, Sandra, Skoric, Luka, Donnelly, Claire, Niño Orti, Miguel A., McGrouther, D., McVitie, Stephen, Flewett, S., Jaouen, N., Belkhou, Rachid, Foerster, Michael, Fernández-Pacheco, Amalio, Engineering and Physical Sciences Research Council (UK), European Commission, Gobierno de Aragón, Agencia Estatal de Investigación (España), Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Ciencia e Innovación (España), Fundación para el Fomento en Asturias de la Investigación Científica Aplicada y la Tecnología, Alexander von Humboldt Foundation, Max Planck Society, Generalitat de Catalunya, Projekt DEAL, Cascales Sandoval, Miguel A., Hierro-Rodríguez, Aurelio, Ruiz-Gómez, Sandra, Skoric, Luka, Donnelly, Claire, Niño Orti, Miguel A., McGrouther, D., McVitie, Stephen, Flewett, S., Jaouen, N., Belkhou, Rachid, Foerster, Michael, and Fernández-Pacheco, Amalio

Abstract

This work presents a detailed analysis of the performance of X-ray magnetic circular dichroism photoemission electron microscopy (XMCD-PEEM) as a tool for vector reconstruction of magnetization. For this, 360° domain wall ring structures which form in a synthetic antiferromagnet are chosen as the model to conduct the quantitative analysis. An assessment is made of how the quality of the results is affected depending on the number of projections that are involved in the reconstruction process, as well as their angular distribution. For this a self-consistent error metric is developed which allows an estimation of the optimum azimuthal rotation angular range and number of projections. This work thus proposes XMCD-PEEM as a powerful tool for vector imaging of complex 3D magnetic structures.

Published
2024

2. Determination of optimal experimental conditions for accurate 3D reconstruction of the magnetization vector via XMCD-PEEM

Author

Cascales-Sandoval, Miguel A., primary, Hierro-Rodriguez, A., additional, Ruiz-Gómez, S., additional, Skoric, L., additional, Donnelly, C., additional, Niño, M. A., additional, McGrouther, D., additional, McVitie, S., additional, Flewett, S., additional, Jaouen, N., additional, Belkhou, R., additional, Foerster, M., additional, and Fernandez-Pacheco, A., additional

Published
2024
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3. Probing 3D magnetic nanostructures by dark-field magneto-optical Kerr effect.

Author

Sanz-Hernández, Dédalo, Skoric, Luka, Cascales-Sandoval, Miguel Ángel, and Fernández-Pacheco, Amalio

Subjects
KERR magneto-optical effect, NANOWIRES, MAGNETIC control, MAGNETIC films, NANOSTRUCTURES, THIN films
Abstract

Magneto-optical techniques are key tools for the characterization of magnetic effects at a nanoscale. Here, we present the dark-field magneto-optical Kerr effect (DFMOKE), a technique we have recently developed for the characterization of three-dimensional magnetic nanostructures. We introduce the principles of DFMOKE, based on the separation of an incident beam into multiple reflected beams when focusing on a 3D nano-geometry. We show the key modifications needed in a standard focused MOKE magnetometer to perform these measurements. Finally, we showcase the power of this method by detecting the magnetic switching of a single tilted 3D nanowire, independently from the switching of a magnetic thin film that surrounds it. We obtain independent and simultaneous switching detection of the nanowire and the film for all nanowire dimensions investigated, allowing us to estimate a magnetic sensitivity of 7 × 10−15 A m2 for DFMOKE in the setup used. We conclude the article by providing perspectives of future avenues where DFMOKE can be a very powerful characterization tool in the future investigations of 3D magnetic nanostructures. [ABSTRACT FROM AUTHOR]

Published
2023
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4. Dataset supporting publication 'Fourier-space generalized magneto-optical ellipsometry'

Author

UK Research and Innovation, Engineering and Physical Sciences Research Council (UK), European Commission, Ministerio de Ciencia e Innovación (España), Gobierno de Aragón, Cascales Sandoval, Miguel A. [m.cascales-sandoval.1@research.gla.ac.uk], Fernández-Pacheco, Amalio [amaliofp@unizar.es], Cascales Sandoval, Miguel A., Hierro-Rodríguez, Aurelio, Sanz-Hernández, Dédalo, Skoric, Luka, Christensen, C. N., Donnelly, Claire, Fernández-Pacheco, Amalio, UK Research and Innovation, Engineering and Physical Sciences Research Council (UK), European Commission, Ministerio de Ciencia e Innovación (España), Gobierno de Aragón, Cascales Sandoval, Miguel A. [m.cascales-sandoval.1@research.gla.ac.uk], Fernández-Pacheco, Amalio [amaliofp@unizar.es], Cascales Sandoval, Miguel A., Hierro-Rodríguez, Aurelio, Sanz-Hernández, Dédalo, Skoric, Luka, Christensen, C. N., Donnelly, Claire, and Fernández-Pacheco, Amalio

Abstract

Raw data for this publication, including Fourier-resolved magneto-optical Kerr effect maps and selected analysis of them, as shown in the paper.

Published
2023

6. Probing 3D magnetic nanostructures by dark-field magneto-optical Kerr effect

Author

University of Cambridge, Agence Nationale de la Recherche (France), Centre National de la Recherche Scientifique (France), European Commission, Gobierno de Aragón, Engineering and Physical Sciences Research Council (UK), Sanz-Hernández, Dédalo, Skoric, Luka, Cascales Sandoval, Miguel A., Fernández-Pacheco, Amalio, University of Cambridge, Agence Nationale de la Recherche (France), Centre National de la Recherche Scientifique (France), European Commission, Gobierno de Aragón, Engineering and Physical Sciences Research Council (UK), Sanz-Hernández, Dédalo, Skoric, Luka, Cascales Sandoval, Miguel A., and Fernández-Pacheco, Amalio

Abstract

Magneto-optical techniques are key tools for the characterization of magnetic effects at the nanoscale. Here, we present the dark-field magneto-optical Kerr effect (DFMOKE), a technique we have recently developed for the characterization of three-dimensional magnetic nanostructures. We introduce the principles of DFMOKE, based on the separation of an incident beam into multiple reflected beams when focusing on a 3D nano-geometry. We show the key modifications needed in a standard focused MOKE magnetometer to perform these measurements. Finally, we showcase the power of this method by detecting the magnetic switching of a single tilted 3D nanowire, independently from the switching of a magnetic thin film that surrounds it. We obtain independent and simultaneous switching detection of the nanowire and the film for all nanowire dimensions investigated, allowing us to estimate a magnetic sensitivity of 7 × 10-15 A m2 for DFMOKE in the setup used. We conclude the article by providing perspectives of future avenues where DFMOKE can be a very powerful characterization tool in future investigations of 3D magnetic nanostructures.

Published
2023

8. Fourier-space generalized magneto-optical ellipsometry

Author

Engineering and Physical Sciences Research Council (UK), European Commission, Gobierno de Aragón, Agencia Estatal de Investigación (España), Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Ciencia e Innovación (España), Fundación para el Fomento en Asturias de la Investigación Científica Aplicada y la Tecnología, Centre National de la Recherche Scientifique (France), Agence Nationale de la Recherche (France), Cascales Sandoval, Miguel A., Hierro-Rodríguez, Aurelio, Sanz-Hernández, Dédalo, Skoric, Luka, Christensen, C. N., Donnelly, Claire, Fernández-Pacheco, Amalio, Engineering and Physical Sciences Research Council (UK), European Commission, Gobierno de Aragón, Agencia Estatal de Investigación (España), Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Ciencia e Innovación (España), Fundación para el Fomento en Asturias de la Investigación Científica Aplicada y la Tecnología, Centre National de la Recherche Scientifique (France), Agence Nationale de la Recherche (France), Cascales Sandoval, Miguel A., Hierro-Rodríguez, Aurelio, Sanz-Hernández, Dédalo, Skoric, Luka, Christensen, C. N., Donnelly, Claire, and Fernández-Pacheco, Amalio

Abstract

The magneto-optical Kerr effect (MOKE) is widely exploited in laboratory-based setups for the study of thin films and nanostructures, providing magnetic characterization with good spatial and temporal resolutions. Due to the complex coupling of light with a magnetic sample, conventional MOKE magnetometers normally work by selecting a small range of incident wave-vector values, focusing the incident light beam to a small spot, and recording the reflected intensity at that angular range by means of photodetectors. Using this approach, additional methodologies and measurements are required for full vectorial magnetic characterization. Here, we computationally investigate a Fourier-space MOKE setup, where a focused beam ellipsometer using high numerical aperture optics and a camera detector is employed to simultaneously map the intensity distribution for a wide range of incident and reflected wave vectors. We employ circularly incident polarized light and no analyzing optics, in combination with a fitting procedure of the light intensity maps to the analytical expression of the Kerr effect under linear approximation. In this way, we are able to retrieve the three unknown components of the magnetization vector as well as the material' s optical and magneto-optical constants with high accuracy and short acquisition times, with the possibility of single-shot measurements. Fourier MOKE is thus proposed as a powerful method to perform generalized magneto-optical ellipsometry for a wide range of magnetic materials and devices.

Published
2023

9. Observation and formation mechanism of 360° domain wall rings in synthetic anti-ferromagnets with interlayer chiral interactions.

Author

Cascales Sandoval, Miguel A., Hierro-Rodríguez, A., Ruiz-Gómez, S., Skoric, L., Donnelly, C., Niño, M. A., Vedmedenko, E. Y., McGrouther, D., McVitie, S., Flewett, S., Jaouen, N., Foerster, M., and Fernández-Pacheco, A.

Subjects
*MAGNETIC circular dichroism, *METASTABLE states, *MAGNETIC fields, *IMAGE reconstruction, *ELECTRON microscopy
Abstract

The interlayer Dzyaloshinskii–Moriya interaction (IL-DMI) chirally couples spins in different ferromagnetic layers of multilayer heterostructures. So far, samples with IL-DMI have been investigated utilizing magnetometry and magnetotransport techniques, where the interaction manifests as a tunable chiral exchange bias field. Here, we investigate the nanoscale configuration of the magnetization vector in a synthetic anti-ferromagnet (SAF) with IL-DMI, after applying demagnetizing field sequences. We add different global magnetic field offsets to the demagnetizing sequence in order to investigate the states that form when the IL-DMI exchange bias field is fully or partially compensated. For magnetic imaging and vector reconstruction of the remanent magnetic states, we utilize x-ray magnetic circular dichroism photoemission electron microscopy, evidencing the formation of 360° domain wall rings of typically 0.5–3.0 μm in diameter. These spin textures are only observed when the exchange bias field due to the IL-DMI is not perfectly compensated by the magnetic field offset. From a combination of micromagnetic simulations, magnetic charge distribution, and topology arguments, we conclude that a non-zero remanent effective field with components both parallel and perpendicular to the anisotropy axis of the SAF is necessary to observe the rings. This work shows how the exchange bias field due to IL-DMI can lead to complex metastable spin states during reversal, important for the development of future spintronic devices. [ABSTRACT FROM AUTHOR]

Published
2023
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10. Supporting Information for Domain wall automotion in three-dimensional magnetic helical interconnectors

Author

Skoric, Luka, Donnelly, Claire, Hierro-Rodríguez, Aurelio, Cascales Sandoval, Miguel A., Ruiz-Gómez, Sandra, Foerster, Michael, Niño Orti, Miguel A., Belkhou, Rachid, Abert, Claas, Suess, Dieter, Fernández-Pacheco, Amalio, Skoric, Luka, Donnelly, Claire, Hierro-Rodríguez, Aurelio, Cascales Sandoval, Miguel A., Ruiz-Gómez, Sandra, Foerster, Michael, Niño Orti, Miguel A., Belkhou, Rachid, Abert, Claas, Suess, Dieter, and Fernández-Pacheco, Amalio

Abstract

X-ray induced bending analysis; simulation structure details; method for calculating DW position; domain wall speed in simulations; Walker breakdown; effects of the mesh size; XAS spectra; shadow-XPEEM image processing; shadow-XPEEM simulation method; measuring DW height in simulations and experiments; domain wall chirality; full details of the angular study.

Published
2022

11. Fourier-space generalized magneto-optical ellipsometry

Author

UK Research and Innovation, European Commission, Ministerio de Ciencia e Innovación (España), Gobierno de Aragón, Agencia Estatal de Investigación (España), Fundación para el Fomento en Asturias de la Investigación Científica Aplicada y la Tecnología, Agence Nationale de la Recherche (France), Centre National de la Recherche Scientifique (France), Engineering and Physical Sciences Research Council (UK), Max Planck Society, Cascales Sandoval, Miguel A., Hierro-Rodríguez, Aurelio, Sanz-Hernández, Dédalo, Skoric, Luka, Christensen, C. N., Donnelly, Claire, Fernández-Pacheco, Amalio, UK Research and Innovation, European Commission, Ministerio de Ciencia e Innovación (España), Gobierno de Aragón, Agencia Estatal de Investigación (España), Fundación para el Fomento en Asturias de la Investigación Científica Aplicada y la Tecnología, Agence Nationale de la Recherche (France), Centre National de la Recherche Scientifique (France), Engineering and Physical Sciences Research Council (UK), Max Planck Society, Cascales Sandoval, Miguel A., Hierro-Rodríguez, Aurelio, Sanz-Hernández, Dédalo, Skoric, Luka, Christensen, C. N., Donnelly, Claire, and Fernández-Pacheco, Amalio

Abstract

The magneto-optical Kerr effect (MOKE) is a widely used lab-based technique for the study of thin films and nanostructures, providing magnetic characterization with good spatial and temporal resolutions. Due to the complex coupling of light with a magnetic sample, conventional MOKE magnetometers normally work by selecting a small range of incident wave-vector values, focusing the incident light beam to a small spot, and recording the reflected intensity at that angular range by means of photodetectors. This generally provides signals proportional to a mixture of magnetization components, requiring additional methodologies for full vectorial magnetic characterization. Here, we computationally investigate a Fourier-space MOKE setup, where a focused beam ellipsometer using high numerical aperture optics and a camera detector is employed to simultaneously map the intensity distribution for a wide range of incident and reflected wave-vectors. We employ circularly incident polarized light and no analyzing optics, in combination with a fitting procedure of the light intensity maps to the analytical expression of the Kerr effect under linear approximation. In this way, we are able to retrieve the three unknown components of the magnetization vector as well as the material's optical and magneto-optical constants with high accuracy and short acquisition times, with the possibility of single shot measurements. Fourier MOKE is thus proposed as a powerful method to perform generalized magneto-optical ellipsometry for a wide range of magnetic materials and devices.

Published
2022

12. Domain wall automotion in three-dimensional magnetic helical interconnectors

Author

Engineering and Physical Sciences Research Council (UK), European Research Council, European Commission, Winton Foundation, University of Cambridge, Isaac Newton Trust, Leverhulme Trust, L'Oréal-UNESCO For Women in Science, Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Gobierno de Aragón, University of Vienna, Austrian Science Fund, Skoric, Luka, Donnelly, Claire, Hierro-Rodríguez, Aurelio, Cascales Sandoval, Miguel A., Ruiz-Gómez, Sandra, Foerster, Michael, Niño Orti, Miguel A., Belkhou, Rachid, Abert, Claas, Suess, Dieter, Fernández-Pacheco, Amalio, Engineering and Physical Sciences Research Council (UK), European Research Council, European Commission, Winton Foundation, University of Cambridge, Isaac Newton Trust, Leverhulme Trust, L'Oréal-UNESCO For Women in Science, Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Gobierno de Aragón, University of Vienna, Austrian Science Fund, Skoric, Luka, Donnelly, Claire, Hierro-Rodríguez, Aurelio, Cascales Sandoval, Miguel A., Ruiz-Gómez, Sandra, Foerster, Michael, Niño Orti, Miguel A., Belkhou, Rachid, Abert, Claas, Suess, Dieter, and Fernández-Pacheco, Amalio

Abstract

The fundamental limits currently faced by traditional computing devices necessitate the exploration of ways to store, compute, and transmit information going beyond the current CMOS-based technologies. Here, we propose a three-dimensional (3D) magnetic interconnector that exploits geometry-driven automotion of domain walls (DWs), for the transfer of magnetic information between functional magnetic planes. By combining state-of-the-art 3D nanoprinting and standard physical vapor deposition, we prototype 3D helical DW conduits. We observe the automotion of DWs by imaging their magnetic state under different field sequences using X-ray microscopy, observing a robust unidirectional motion of DWs from the bottom to the top of the spirals. From experiments and micromagnetic simulations, we determine that the large thickness gradients present in the structure are the main mechanism for 3D DW automotion. We obtain direct evidence of how this tailorable magnetic energy gradient is imprinted in the devices, and how it competes with pinning effects that are due to local changes in the energy landscape. Our work also predicts how this effect could lead to high DW velocities, reaching the Walker limit during automotion. This work demonstrates a possible mechanism for efficient transfer of magnetic information in three dimensions.

Published
2022

13. Dataset supporting publication 'Domain wall automotion in three-dimensional magnetic helical interconnectors'

Author

Engineering and Physical Sciences Research Council (UK), European Commission, University of Cambridge, Leverhulme Trust, Isaac Newton Trust, L'Oréal, United Nations Educational, Scientific and Cultural Organization, Agencia Estatal de Investigación (España), University of Vienna, Skoric, Luka [ls604@cam.ac.uk], Fernández-Pacheco, Amalio [amaliofp@unizar.es], Skoric, Luka, Donnelly, Claire, Hierro-Rodríguez, Aurelio, Cascales Sandoval, Miguel A., Ruiz-Gómez, Sandra, Foerster, Michael, Niño Orti, Miguel A., Belkhou, Rachid, Abert, Claas, Suess, Dieter, Fernández-Pacheco, Amalio, Engineering and Physical Sciences Research Council (UK), European Commission, University of Cambridge, Leverhulme Trust, Isaac Newton Trust, L'Oréal, United Nations Educational, Scientific and Cultural Organization, Agencia Estatal de Investigación (España), University of Vienna, Skoric, Luka [ls604@cam.ac.uk], Fernández-Pacheco, Amalio [amaliofp@unizar.es], Skoric, Luka, Donnelly, Claire, Hierro-Rodríguez, Aurelio, Cascales Sandoval, Miguel A., Ruiz-Gómez, Sandra, Foerster, Michael, Niño Orti, Miguel A., Belkhou, Rachid, Abert, Claas, Suess, Dieter, and Fernández-Pacheco, Amalio

Published
2022

14. Domain Wall Automotion in Three-Dimensional Magnetic Helical Interconnectors

Author

Skoric, Luka, primary, Donnelly, Claire, additional, Hierro-Rodriguez, Aurelio, additional, Cascales Sandoval, Miguel A., additional, Ruiz-Gómez, Sandra, additional, Foerster, Michael, additional, Niño, Miguel A., additional, Belkhou, Rachid, additional, Abert, Claas, additional, Suess, Dieter, additional, and Fernández-Pacheco, Amalio, additional

Published
2022
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