Development of TEM Holder Generating In-Plane Magnetic Field Used for &lt;i&gt;In-Situ&lt;/i&gt; TEM Observation

Arita, Masashi; Tokuda, Ryohei; Hamada, K.; Takahashi, Yasuo

doi:10.2320/matertrans.md201310

Cited by 25 publications

(7 citation statements)

References 46 publications

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“…A number of approaches have been proposed, including tilting the sample into the field of the objective lens or using a sample holder to which small electromagnets are mounted. Further sophistication can be achieved by combining application of a magnetic field with application of current, as shown by Arita et al [10] who showed the use of LTEM to image domain walls injected into Permalloy wires using a holder that they had developed. One of the issues associated with in situ applied fields is deflection of the incident electron beam, and although the holder developed by Arita et al is limited to an applied field of ±200 Oe, an advantage of its design is that the deflection of the electron beam by the applied field is compensated by a second set of magnetizing coils mounted on the holder.…”

Section: Imaging Magnetization Reversal Behaviormentioning

confidence: 99%

Recent advances in Lorentz microscopy

Phatak

Petford‐Long

Graef

2016

Current Opinion in Solid State and Materials Science

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Lorentz transmission electron microscopy (LTEM) has evolved from a qualitative magnetic domain observation technique to a quantitative technique for the determination of the magnetization state of a sample. In this review article, we describe recent developments in techniques and imaging modes, including the use of spherical aberration correction to improve the spatial resolution of LTEM into the single nanometer range, and novel in situ observation modes. We review recent advances in the modeling of the wave optical magnetic phase shift as well as in the area of phase reconstruction by means of the Transport of Intensity Equation (TIE) approach, and discuss vector field electron tomography, which has emerged as a powerful tool for the 3D reconstruction of magnetization configurations. We conclude this review with a brief overview of recent LTEM applications.

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Section: Imaging Magnetization Reversal Behaviormentioning

confidence: 99%

Recent advances in Lorentz microscopy

Phatak

Petford‐Long

Graef

2016

Current Opinion in Solid State and Materials Science

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“…However, due to the deflection of electron trajectories by magnetic fields, these techniques do not easily allow for the application of an in-plane magnetic field 18 .…”

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confidence: 99%

Real-space imaging of confined magnetic skyrmion tubes

et al. 2020

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Magnetic skyrmions are topologically nontrivial particles with a potential application as information elements in future spintronic device architectures 1, 2 . While they are commonly portrayed as two dimensional objects, in reality magnetic skyrmions are thought to exist as elongated, tube-like objects extending through the thickness of the sample 3, 4 . The study of this skyrmion tube (SkT) state is highly relevant for investigating skyrmion metastability 5 and for implementation in recently proposed magnonic computing 6 . However, direct experimental imaging of skyrmion tubes has yet to be reported. Here, we demonstrate the first real-space observation of skyrmion tubes in a lamella of FeGe using resonant magnetic x-ray imaging and comparative micromagnetic simulations, confirming their extended structure.The formation of these structures at the edge of the sample highlights the importance of confinement and edge effects in the stabilisation of the SkT state, opening the door to further investigations into this unexplored dimension of the skyrmion spin texture.Skyrmion states are typically stabilised by the interplay of the ferromagnetic exchange and Zeeman energies with the Dzyalohsinskii-Moriya Interaction (DMI) 7 . In ferromagnet/heavy metal multilayer thin films, interfacial DMI is induced by symmetry-breaking spin-orbit coupling at the interface between the layers, leading to the formation of Néel-type skyrmions [8][9][10] . Bulk DMI, arising due to the lack of centrosymmetry in the underlying crystal lattice, is responsible for the formation of Bloch-type skyrmions in a range of chiral ferromagnets [11][12][13][14][15] . In crystals of these bulk materials the skyrmion state is typically only at equilibrium in a limited range of applied magnetic field and temperature just below the Curie temperature, T c , forming a hexagonal skyrmion lattice (SkL) in a plane perpendicular to the applied magnetic field.2 Figure 1 | Visualisation of the skyrmion tube spin texture. Three dimensional visualisation of three magnetic skyrmion tubes from the micromagnetic simulations presented in this paper, illustrating their extended spin structure. The inset highlights the location of the magnetic Bloch point at the end of each skyrmion tube. 3The three dimensional visualisation in Fig. 1 depicts the extended spin structure of three magnetic skyrmion tubes. The dynamics of this skyrmion tube (SkT) state play an important role in the creation and annihilation of skyrmions. For example, metastable skyrmions, which are created beyond the equilibrium thermal range by rapid field cooling 16 , are thought to unwind into topologically trivial magnetic states through the motion of a magnetic Bloch point located at the end of each individual skyrmion tube 3, 5 . Real-space observation of this dimension of the SkT state and its associated dynamics requires an in-plane magnetic field applied perpendicular to the imaging axis. Electron imaging techniques such as Fresnel Lorentz Transmission Electron Microscopy (LTEM) 12, 13 , and elec...

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“…This procedure just requires a set of ending states produced by reversing the magnetization. The maximum pulsed magnetic field of 415 kA/m is larger than those of less 72 kA/m in the previously developed magnetization systems placed on 26 , 27 and around 12 , 28 the sample holder, which were designed to perform in-situ observation of the magnetic behaviour in a steady applied magnetic field. The developed system can be widely used to reverse the magnetization in hard magnets or magnets with a large shape effect, as demonstrated in a thin oxide magnet by applying a 207-kA/m pulsed magnetic field (Supplementary Information).…”

Section: Resultsmentioning

confidence: 99%

Magnetic field observations in CoFeB/Ta layers with 0.67-nm resolution by electron holography

Tanigaki

Akashi

Sugawara

et al. 2017

Sci Rep

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Nanometre-scale magnetic field distributions in materials such as those at oxide interfaces, in thin layers of spintronics devices, and at boundaries in magnets have become important research targets in materials science and applied physics. Electron holography has advantages in nanometric magnetic field observations, and the realization of aberration correctors has improved its spatial resolution. Here we show the subnanometre magnetic field observations inside a sample at 0.67-nm resolution achieved by an aberration-corrected 1.2-MV holography electron microscope with a pulse magnetization system. A magnetization reduction due to intermixing in a CoFeB/Ta multilayer is analyzed by observing magnetic field and electrostatic potential distributions simultaneously. Our results demonstrate that high-voltage electron holography can be widely applied to pin-point magnetization analysis with structural and composition information in physics, chemistry, and materials science.

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Development of TEM Holder Generating In-Plane Magnetic Field Used for <i>In-Situ</i> TEM Observation

Cited by 25 publications

References 46 publications

Recent advances in Lorentz microscopy

Recent advances in Lorentz microscopy

Real-space imaging of confined magnetic skyrmion tubes

Magnetic field observations in CoFeB/Ta layers with 0.67-nm resolution by electron holography

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