Kim Duck-Ho, Okuno Takaya, Kim Se Kwon, Oh Se-Hyeok, Nishimura Tomoe, Hirata Yuushou, Futakawa Yasuhiro, Yoshikawa Hiroki, Tsukamoto Arata, Tserkovnyak Yaroslav, Shiota Yoichi, Moriyama Takahiro, Kim Kab-Jin, Lee Kyung-Jin, Ono Teruo
Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
Department of Physics and Astronomy, University of California Los Angeles, California 90095, USA.
Phys Rev Lett. 2019 Mar 29;122(12):127203. doi: 10.1103/PhysRevLett.122.127203.
We investigate the Gilbert damping parameter α for rare earth (RE)-transition metal (TM) ferrimagnets over a wide temperature range. Extracted from the field-driven magnetic domain-wall mobility, α was as low as the order of 10^{-3} and was almost constant across the angular momentum compensation temperature T_{A}, starkly contrasting previous predictions that α should diverge at T_{A} 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.
我们在很宽的温度范围内研究了稀土（RE）-过渡金属（TM）亚铁磁体的吉尔伯特阻尼参数α。从场驱动磁畴壁迁移率中提取的α低至10⁻³量级，并且在角动量补偿温度TA范围内几乎保持恒定，这与之前的预测形成鲜明对比，之前预测α在TA处会因总角动量消失而发散。因此，RE-TM亚铁磁体的磁阻尼与总角动量无关，而是由费米能级处的电子散射主导，其中TM具有主要的阻尼作用。吉尔伯特阻尼参数的这一低值表明，亚铁磁体可作为低耗散高速磁器件的通用平台。
