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Proceedings Paper

Correlation of the Dzyaloshinskii-Moriya Interaction with Heisenberg exchange and orbital asphericity (Conference Presentation)
Author(s): Sanghoon Kim; Kohei Ueda; Gyungchoon Go; Peong-Hwa Jang; Kyung-Jin Lee; Abderrezak Belabbes; Aurelien Manchon; Motohiro Suzuki; Yoshinori Kotani; Tetsuya Nakamura; Kohji Nakamura; Tomohiro Koyama; Daichi Chiba; Kihiro Yamada; Duck-Ho Kim; Takahiro Moriyama; Kab-Jin Kim; Teruo Ono
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Paper Abstract

Spin-related phenomena, such as the giant magnetoresistance and the spin-transfer torque, have led to a new era of nano-spintronics in last two decades. The discovery of these physical phenomena has contributed to a substantial increase in the data storage capacity of computers. Another revolutionary phenomenon, the interfacial Dzyaloshinskii-Moriya interaction (DMI), was recently discovered in ultra-thin ferromagnet/heavy-metal bilayers. The DMI stabilizes nanometre-sized chiral spin textures such as Néel domain walls and hedgehog skyrmions. These chiral objects find the potential for applications in ultra-high density, low-energy, and high-speed memory devices because they are stable due to topological protection and easy to move with high efficiency. As both stability and current-driven speed of chiral spin textures are proportional to the DMI strength [A. Thiaville et al., Europhys Lett. 100, 57002 (2012); A. Fert, V. Cros, and J. Sampiao, Nat. Nanotechnol. 8, 152 (2013)], tremendous efforts are being devoted to finding high-DMI materials. In this respect, understanding the microscopic origin of DMI is of critical importance. Here we discuss the microscopic origin of the interfacial DMI with experimental and theoretical studies as follows: First, we show the temperature dependence of the DMI for a Pt/Co/MgO trilayer; the DMI increases with decreasing temperature in a range from 300 to 100 K. To discuss this temperature dependence of the DMI, that of the spin and orbital magnetic moments of Co and Pt is studied by X-ray magnetic circular dichroism (XMCD) spectroscopy. We find that spin moment values of Co and Pt show temperature dependences due to change in Heisenberg exchange. Furthermore, the intra-atomic magnetic dipole moment, which is due to the asymmetric spin-density distribution, shows strong temperature dependence, suggesting a sizable modification of the charge distribution between the in-plane and the out-of-plane d-orbitals under temperature variation. We also find that the out-of-plane orbital moment shows large temperature dependence while in-plane orbital moment does not, revealing a close connection between the anisotropy of orbital moment and the DMI. The ab-initio and the tight-binding model calculations suggest that the ISB-dependent electron hopping, which gives rise to the asymmetric charge distribution at the interface of the FM/HM, is a possible microscopic origin of the correlation between the orbital anisotropy and the DMI.

Paper Details

Date Published: 18 September 2018
Proc. SPIE 10732, Spintronics XI, 107322N (18 September 2018); doi: 10.1117/12.2322342
Show Author Affiliations
Sanghoon Kim, Univ. of Ulsan (Korea, Republic of)
Kohei Ueda, Massachusetts Institute of Technology (United States)
Gyungchoon Go, Korea Univ. (Korea, Republic of)
Peong-Hwa Jang, Korea Univ. (Korea, Republic of)
Kyung-Jin Lee, Korea Univ. (Korea, Republic of)
Abderrezak Belabbes, King Abdullah Univ. of Science and Technology (Saudi Arabia)
Aurelien Manchon, King Abdullah Univ. of Science and Technology (Korea, Republic of)
Motohiro Suzuki, SPring-8 (Japan)
Yoshinori Kotani, SPring-8 (Japan)
Tetsuya Nakamura, SPring-8 (Japan)
Kohji Nakamura, Mie Univ. (Japan)
Tomohiro Koyama, The Univ. of Tokyo (Japan)
Daichi Chiba, The Univ. of Tokyo (Japan)
Kihiro Yamada, Kyoto Univ. (Japan)
Duck-Ho Kim, Kyoto Univ. (Japan)
Takahiro Moriyama, Kyoto Univ. (Japan)
Kab-Jin Kim, KAIST (Korea, Republic of)
Teruo Ono, Kyoto Univ. (Japan)

Published in SPIE Proceedings Vol. 10732:
Spintronics XI
Henri-Jean Drouhin; Jean-Eric Wegrowe; Manijeh Razeghi; Henri Jaffrès, Editor(s)

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