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Focuses on a study which described a method of reconstructing three-dimensional magnetic fields using electron-holographic interferometry. Analysis of a measured two-dimensional phase distributions to reveal the projected magnetic flux structure of a microscopic object; Development of an algorithm for reconstructing the magnetic flux density in three dimension from the phase distributions at different viewing directions; Presentation of an application to a barium particle.

Examines the sensitivity-enhanced electron holography and its application to magnetic recording investigations. Information on the quantitative measurement of magnetic flux; Distribution of a leakage magnetic field; Calculation of the magnetic field vector component.

Skyrmions are nanoscale spin textures that are viewed as promising candidates as information carriers in future spintronic devices. Skyrmions have been observed using neutron scattering and microscopy techniques. Real-space imaging using electrons is a straightforward way to interpret spin configurations by detecting the phase shifts due to electromagnetic fields. Here, we report the first observation by electron holography of the magnetic flux and the three-dimensional spin configuration of a skyrmion lattice in Fe0.5Co0.5Si thin samples. The magnetic flux inside and outside a skyrmion was directly visualized and the handedness of the magnetic flux flow was found to be dependent on the direction of the applied magnetic field. The electron phase shifts φ in the helical and skyrmion phases were determined using samples with a stepped thickness t (from 55 nm to 510 nm), revealing a linear relationship (φ = 0.00173t). The phase measurements were used to estimate the three-dimensional structures of both the helical and skyrmion phases, demonstrating that electron holography is a useful tool for studying complex magnetic structures and for three-dimensional, real-space mapping of magnetic fields. [ABSTRACT FROM AUTHOR]

The magnetic interaction between the pole tip of a single-pole head and a pseudo soft underlayer in perpendicular magnetic recording was observed by electron holography. The magnetic flux density inside the soft underlayer was quantitatively evaluated. The distribution of magnetic flux density was calculated using the finite element method, and the influences of the modulation of the reference wave and stray fields were investigated by comparison with experimental results. The flux density observed was found to be underestimated due to the modulation of the phase shift in reference wave. The magnetic flux measured experimentally was larger than that inside the specimen because of the relatively large stray fields above and below the specimen in the direction of the electron beam. [ABSTRACT FROM AUTHOR]