KENBIKYO Vol.48▶No.1 2013
■Feature Articles: Spin-Polarized Electron Technology

Spin-Polarized Scanning Electron Microscopy (Spin SEM)

Teruo Kohashi

Hitachi, Ltd., Central Research Laboratory

Abstract: magnetic domain, spin SEM, spin polarization, sample heating system

Key words: A spin-polarized scanning electron microscope (spin SEM) is a unique method for observing the magnetic domain structures in high resolution. It uses the phenomenon where the spin-polarization vector of secondary electrons emitted from ferromagnetic material is related to the magnetization vector at the originating point of the secondary electrons on the material. The spin polarization of the secondary electrons is detected by the spin polarimeter, which is a key component of spin SEM. The spin polarimeter is based on the Mott scattering, and all three spin polarization components can be analyzed by functioning the spin manipulator with the spin polarimeter.
Spin SEM has several advantages besides the high resolution, such as no limitation for sample thickness and flatness, magnetization information independent from the sample surface topography, and quantitative analysis of the magnetization vectors in three dimensions. In this paper, the principle of spin SEM and the spin polarimeter are explained and spin SEM data of HDD recording medium are introduced. At the end, the observation of the magnetic domains on Co crystal up to 500 ℃ is shown.