Nonreciprocal coherent coupling of nanomagnets by exchange spin waves
Hanchen Wang, Jilei Chen, Tao Yu, Chuanpu Liu, Chenyang Guo, Song Liu, Ka Shen, Hao Jia, Tao Liu, Jianyu Zhang, Marco A. Cabero, Qiuming Song, Sa Tu, Mingzhong Wu, Xiufeng Han, Ke Xia, Dapeng Yu, Gerrit E. W. Bauer, Haiming Yu
Abstract
Nanomagnets are widely used to store information in non-volatile spintronic devices. Spin waves can transfer information with low-power consumption as their propagations are independent of charge transport. However, to dynamically couple two distant nanomagnets via spin waves remains a major challenge for magnonics. Here we experimentally demonstrate coherent coupling of two distant Co nanowires by fast propagating spin waves in an yttrium iron garnet thin film with sub-50 nm wavelengths. Magnons in two nanomagnets are unidirectionally phase-locked with phase shifts controlled by magnon spin torque and spin-wave propagation. The coupled system is finally formulated by an analytical theory in terms of an effective non-Hermitian Hamiltonian. Our results are attractive for analog neuromorphic computing that requires unidirectional information transmission.