Control of domain wall position in L-shaped Fe4N negatively spin polarized ferromagnetic nanowire

• Published in: 2015 IEEE Magnetics Conference (INTERMAG) p. 1
• Main Authors: Gushi, T., Ito, K., Honda, S., Yasutomi, Y., Higashikozono, S., Toko, K., Oosato, H., Sugimoto, Y., Asakawa, K., Ota, N., Suemasu, T.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.05.2015
• Subjects: Aluminum oxide; Epitaxial growth; Nanotechnology; Torque; Wires; X-ray scattering
• ISSN: 2150-4598; 2150-4601
• DOI: 10.1109/INTMAG.2015.7157071

Current-driven magnetic domain wall (DW) motion has been extensively studied not only theoretically, but also experimentally. The DW motion is induced by spin-transfer torque, that is, the transfer of spin angular momentum from conduction electrons to localized electrons. The velocity of DW motion is proportional to the spin polarization [P a = (σ ↑ - σ ↓ )/(σ ↑ + σ ↓ )] of electrical conductivity (σ) and its direction is the same as electron current when P σ > 0. The reverse DW motion is thus expected in ferromagnetic materials with negative spin polarization (P σ <; 0) compared to those with positive spin polarization, because minority spin dominates the electrical conduction. Thereby, spintronics devices composed of both a positive P σ material and a negative P σ material, are of fundamental interest. We have paid a lot of attention to ferromagnetic Fe 4 N epitaxial films for application to spintronics devices because it is theoretically expected to have a large negative spin polarization (P σ = -1.0). Very recently, we confirmed its negative spin polarization by experiment.