学术报告（2024年12月16日15:00）：单轴反铁磁绝缘体中D'yakonov-Perel'类型磁子自旋驰豫的实验观测

主  持  人：侯玉升副教授

报告摘要：Long-distance transport of magnon spin currents in antiferromagnetic (AFM) insulators is essential for the development of magnonics, however, their relaxation mechanisms remain unclear. Experimentally, we reveal that the D’yakonov-Perel’-type magnon spin relaxation mechanism governs non-local spin current transport in two prototypical uniaxial AFM insulators, Cr2O3 and α-Fe2O3. Three key pieces of evidence will be presented. (1) A significant enhancement of non-local spin currents is observed prior to the spin-flop transition, which cannot be fitted by an established magnon-gap-closure model but is well-interpreted by our model incorporating D’yakonov-Perel’-type magnon spin relaxation. (2) We find that the magnon spin diffusion length in Cr2O3 increases by 35% at 35 K, from 0.63 μm at zero magnetic field to 0.85 μm above 1.00 Tesla, consistent with the D’yakonov-Perel’-type magnon spin relaxation model. (3) Temperature dependence of the zero-field magnon spin diffusion length and magnon momentum scattering time in both AFM insulators can be qualitatively explained very well through our model. We believe these findings provide valuable insights for the development of low-dissipation antiferromagnetic spintronic devices.

报告人简介：李军学，2015在复旦大学物理系获得凝聚态物理博士学位，2015年3月至2020年9月期间在加州大学河滨分校物理与天文系从事博士后研究，2020年12月加盟南科大物理系（现为准聘副教授），并于次年获得深圳市“国家级领军人才”称号及国家青年人才计划支持。李军学博士的主要研究兴趣集中于探索纳米尺度电子器件与异质结中的自旋相关的新奇物理现象，这些现象一般起源于物质内部或者器件界面的复杂相互作用；另一方面，对于新兴的量子材料和磁性材料，他对于利用分子束外延和脉冲激光沉积技术生长单晶外延薄膜也非常感兴趣。李军学博士共发表学术论文35篇，其中以第一作者及共同一作身份发表论文10篇，包括Nature (1篇)，Nat. Commun. (2篇)，Phy. Rev. Lett. (2篇)，Nano Lett. (1篇)，Phy. Rev. B (2 篇)等。截止目前，其谷歌学术引用为1952次，H因子为21。