Zhang Jianyu, Chen Mingfeng, Chen Jilei, Yamamoto Kei, Wang Hanchen, Hamdi Mohammad, Sun Yuanwei, Wagner Kai, He Wenqing, Zhang Yu, Ma Ji, Gao Peng, Han Xiufeng, Yu Dapeng, Maletinsky Patrick, Ansermet Jean-Philippe, Maekawa Sadamichi, Grundler Dirk, Nan Ce-Wen, Yu Haiming
Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, China.
State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, China.
Nat Commun. 2021 Dec 14;12(1):7258. doi: 10.1038/s41467-021-27405-2.
Magnons can transfer information in metals and insulators without Joule heating, and therefore are promising for low-power computation. The on-chip magnonics however suffers from high losses due to limited magnon decay length. In metallic thin films, it is typically on the tens of micrometre length scale. Here, we demonstrate an ultra-long magnon decay length of up to one millimetre in multiferroic/ferromagnetic BiFeO(BFO)/LaSrMnO(LSMO) heterostructures at room temperature. This decay length is attributed to a magnon-phonon hybridization and is more than two orders of magnitude longer than that of bare metallic LSMO. The long-distance modes have high group velocities of 2.5 km s as detected by time-resolved Brillouin light scattering. Numerical simulations suggest that magnetoelastic coupling via the BFO/LSMO interface hybridizes phonons in BFO with magnons in LSMO to form magnon-polarons. Our results provide a solution to the long-standing issue on magnon decay lengths in metallic magnets and advance the bourgeoning field of hybrid magnonics.
磁振子可以在金属和绝缘体中传输信息而不产生焦耳热，因此在低功耗计算方面很有前景。然而，片上磁振子学由于磁振子衰减长度有限而存在高损耗问题。在金属薄膜中，其典型长度尺度在几十微米。在此，我们展示了在室温下多铁性/铁磁性BiFeO（BFO）/LaSrMnO（LSMO）异质结构中高达一毫米的超长磁振子衰减长度。这种衰减长度归因于磁振子 - 声子杂化，比纯金属LSMO的衰减长度长两个多数量级。通过时间分辨布里渊光散射检测到，长距离模式具有2.5千米/秒的高群速度。数值模拟表明，通过BFO/LSMO界面的磁弹耦合使BFO中的声子与LSMO中的磁振子杂化，形成磁振子极化子。我们的结果为金属磁体中磁振子衰减长度这一长期存在的问题提供了解决方案，并推动了新兴的混合磁振子学领域的发展。
