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Start Over Descriptor "magnetization states" Topic magnetic anisotropy
3 results on '"magnetization states"'

1. Defect‐Driven Magnetization Configuration of Isolated Linear Assemblies of Iron Oxide Nanoparticles

Author

Riccardo Hertel, Attila Kákay, Sylvie Begin-Colin, Ebenezer Tetsi, Mircea V. Rastei, V. Pierron-Bohnes, Benoit P. Pichon, Delphine Toulemon, Corinne Bouillet, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, and Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)

Subjects
Materials science, Magnetic domain, AFM / MFM, magnetization states, Nanoparticle, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, e-holography, HR-TEM, Biomaterials, Magnetization, chemistry.chemical_compound, micromagnetic simulations, Electrochemistry, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], One-NP-wide chains, Magnetic structure, Condensed matter physics, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 3. Good health, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, Magnetic anisotropy, chemistry, Particle, Magnetic force microscope, 0210 nano-technology, Iron oxide nanoparticles
Abstract

International audience; The magnetization state of one-dimensional magnetic nanoparticle chains plays a key role for a wide range of applications ranging from diagnosis and therapy in medicine to actuators, sensors and quantum recording media. The interplay between the exact particle orientation and the magnetic anisotropy is in turn crucial for controlling the overall magnetization state with high precision. Here, we report on a three-dimensional description of the magnetic structure of one-NP-wide chains. In this aim, we combined two complementary experimental techniques, magnetic force microscopy (MFM) and electronic holography (EH) which are sensitive to out-of-plane and in-plane magnetization components, respectively. We extended our approach to micromagnetic simulations which provided results in good agreement with MFM and EH. The findings are at variance with the known results on unidirectional nanoparticle assemblies, and show that magnetization is rarely strictly collinear to the chain axis. The magnetic structure of one-NP-wide chains can be interpreted as head-to-head magnetic domain structures with off-axis magnetization components, which is very sensitive to morphological defects in the chain structure such as minute size variation of NPs, tiny misalignment of NPs and/or crystal orientation with respect to easy magnetization axis.

Published
2019

2. Magnetization states driven by spin-transfer torque in spin-valve nanopillars in presence of four-fold magnetocrystalline anisotropy.

Author

Belrhazi, Hamza, Hafidi, Moulay Youssef El, and Hafidi, Mohamed El

Subjects
*MAGNETIC anisotropy, *MAGNETIZATION, *DEMAGNETIZATION, *SPIN-polarized currents, *HEUSLER alloys, *TORQUE, *DENSITY currents
Abstract

• Magnetization states under the spin-transfer effect are elucidated in a Co 1.5 Fe 1.5 Ge nanopillar alloy. • A comparative study has been accomplished by numerically solving the Landau-Lifshitz-Gilbert equation with the Spin-Transfer Torque contributions. • Single-step magnetization switching under weak spin-polarized currents is possible for well-adjusted dimensions. In this work, the magnetization states under the spin-transfer switching effect are investigated in a nanopillar device composed of a half-metallic Heusler Co 1.5 F e 1.5 G e alloy with a four-fold in-plane magnetocrystalline anisotropy. A comparative study with a half-metallic Heusler alloy of Co 2 F e A l 0.5 S i 0.5 and a typical material of Fe is realized by numerically solving the Landau-Lifshitz-Gilbert (LLG) equation with the Spin-Transfer Torque (STT) contribution, using micromagnetic simulations. Our ultimate goal is to elucidate the origins of the intermediate state (IS) that occurs during magnetization switching by deeply examining the effects of magnetocrystalline anisotropy and shape anisotropy on the magnetization states through analyzing and comparing various switching processes. Our simulation results showed that the magnetization switching via a single-step under low current densities is possible at certain critical cross-sectional dimensions of the ellipse that are adjusted to increase the demagnetization field against the four-fold in-plane magnetocrystalline anisotropy. As well, we provided in this paper a set of appropriate geometric dimensions which allow the magnetization to reverse via a single-step by overcoming IS with minimal spin-polarized current densities. [ABSTRACT FROM AUTHOR]

Published
2020
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3. Defect‐Driven Magnetization Configuration of Isolated Linear Assemblies of Iron Oxide Nanoparticles.

Author

Rastei, Mircea V., Pierron‐Bohnes, Véronique, Toulemon, Delphine, Bouillet, Corinne, Kákay, Attila, Hertel, Riccardo, Tetsi, Ebenezer, Begin‐Colin, Sylvie, and Pichon, Benoit P.

Subjects
*MAGNETIC nanoparticle hyperthermia, *MAGNETIZATION, *MAGNETIC structure, *MAGNETIC force microscopy, *MAGNETIC domain, *MAGNETIC anisotropy, *IRON oxide nanoparticles
Abstract

The magnetization state of 1D magnetic nanoparticle (NP) chains plays a key role in a wide range of applications ranging from diagnosis and therapy in medicine to actuators, sensors, and quantum recording media. The interplay between the exact particle orientation and the magnetic anisotropy is in turn crucial for controlling the overall magnetization state with high precision. Here, a 3D description of the magnetic structure of one‐NP‐wide chains is reported. Here, two complementary experimental techniques are combined, magnetic force microscopy (MFM) and electronic holography (EH) which are sensitive to out‐of‐plane and in‐plane magnetization components, respectively. The approach to micromagnetic simulations is extended, which provides results in good agreement with MFM and EH. The findings are at variance with the known results on unidirectional NP assemblies, and show that magnetization is rarely strictly collinear to the chain axis. The magnetic structure of one‐NP‐wide chains can be interpreted as head‐to‐head magnetic domain structures with off‐axis magnetization components, which is very sensitive to morphological defects in the chain structure such as minute size variation of NPs, tiny misalignment of NPs, and/or crystal orientation with respect to easy magnetization axis. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
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