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Your search keyword '"Duck-Ho Kim"' showing total 3 results
Start Over Author "Duck-Ho Kim" Journal physical review letters
3 results on '"Duck-Ho Kim"'

2. Distinct Universality Classes of Domain Wall Roughness in Two-DimensionalPt/Co/PtFilms

Author

Duck-Ho Kim, Kyung-Ho Shin, Sang-Cheol Yoo, Cheong-Gu Cho, Byungnam Kahng, Sungmin Hwang, Sung-Bong Choe, Byoung-Chul Min, and Kyoung-Woong Moon

Subjects
Imagination, Materials science, Condensed matter physics, Creep, media_common.quotation_subject, General Physics and Astronomy, Torque, Surface finish, Science, technology and society, media_common, Universality (dynamical systems), Magnetic field
Abstract

We demonstrate here that the current-driven domain wall (DW) in two dimensions forms a ``facet'' roughness, distinctive to the conventional self-affine roughness induced by a magnetic field. Despite the different universality classes of these roughnesses, both the current- and field-driven DW speed follow the same creep law only with opposite angular dependences. Such angular dependences result in a stable facet angle, from which a single DW image can unambiguously quantify the spin-transfer torque efficiency, an essential parameter in DW-mediated nanodevices.

Published
2013

3. Low Magnetic Damping of Ferrimagnetic GdFeCo Alloys.

Author

Duck-Ho Kim, Takaya Okuno, Se Kwon Kim, Se-Hyeok Oh, Tomoe Nishimura, Yuushou Hirata, Yasuhiro Futakawa, Hiroki Yoshikawa, Arata Tsukamoto, Yaroslav Tserkovnyak, Yoichi Shiota, Takahiro Moriyama, Kab-Jin Kim, Kyung-Jin Lee, and Teruo Ono

Subjects
*ELECTRON scattering, *RARE earth metals, *ANGULAR momentum (Mechanics), *MAGNETIC devices, *FERMI level, *FERRIMAGNETIC materials
Abstract

We investigate the Gilbert damping parameter a for rare earth (RE)-transition metal (TM) ferrimagnets over a wide temperature range. Extracted from the field-driven magnetic domain-wall mobility, a was as low as the order of 10-3 and was almost constant across the angular momentum compensation temperature TA, starkly contrasting previous predictions that α should diverge at TA due to a vanishing total angular momentum. Thus, magnetic damping of RE-TM ferrimagnets is not related to the total angular momentum but is dominated by electron scattering at the Fermi level where the TM has a dominant damping role. This low value of the Gilbert damping parameter suggests that ferrimagnets can serve as versatile platforms for low-dissipation high-speed magnetic devices. [ABSTRACT FROM AUTHOR]

Published
2019
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