Fan Yabin, Fakhrul Takian, Hou Justin T, Chou Chung-Tao, Khurana Bharat, Tserkovnyak Yaroslav, Liu Luqiao, Ross Caroline A
Massachusetts Institute of Technology, Department of Materials Science and Engineering, Cambridge, Massachusetts 02139, USA.
Bangladesh University of Engineering and Technology, Department of Materials and Metallurgical Engineering, Dhaka 1000, Bangladesh.
Phys Rev Lett. 2025 Mar 28;134(12):126702. doi: 10.1103/PhysRevLett.134.126702.
We experimentally explore the interfacial coherent spin pumping in the magnon-magnon hybridized regime of a perpendicular anisotropy ferrimagnetic insulator (Bi-substituted yttrium iron garnet, or BiYIG) and ferromagnetic metal (permalloy, or Py) bilayer. In addition to the interfacial exchange coupling-induced avoided crossings between the uniform modes of BiYIG and Py, we observe that the gap opening can be tailored by changing the relative orientations of the BiYIG and Py magnetizations due to a purely dynamic interaction. The avoided-crossing gap opening is small (large) when BiYIG and Py magnetizations are nearly perpendicular (partially collinear) to each other, indicating that interfacial fieldlike torque from spin pumping plays a dominant role. Macrospin simulations with a sizable fieldlike spin-pumping torque agree with the gap opening trend observed in the experiments.
我们通过实验研究了垂直各向异性亚铁磁绝缘体（铋取代钇铁石榴石，或BiYIG）与铁磁金属（坡莫合金，或Py）双层的磁振子-磁振子杂化体系中的界面相干自旋泵浦。除了界面交换耦合导致BiYIG和Py的均匀模式之间出现避免交叉外，我们还观察到，由于纯动态相互作用，能隙的打开可以通过改变BiYIG和Py磁化强度的相对取向来调整。当BiYIG和Py的磁化强度几乎相互垂直（部分共线）时，避免交叉的能隙打开较小（较大），这表明自旋泵浦产生的界面类场转矩起主导作用。具有相当大的类场自旋泵浦转矩的宏观自旋模拟结果与实验中观察到的能隙打开趋势一致。
