Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA.
Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA.
Phys Rev Lett. 2018 Nov 16;121(20):207202. doi: 10.1103/PhysRevLett.121.207202.
Collinear antiferromagnets (AFs) support two degenerate magnon excitations carrying opposite spin polarizations, by which magnons can function as electrons in various spin-related phenomena. In an insulating ferromagnet(F)/AF/F trilayer, we explore the magnon-mediated interlayer coupling by calculating the magnon thermal energy in the AF as a function of the orientations of the Fs. The effect manifests as an interlayer exchange interaction and a perpendicular magnetic anisotropy; they both depend on temperature and the AF thickness. In particular, the exchange interaction turns out to be antiferromagnetic at low temperatures and ferromagnetic at high temperatures, whose magnitude can be 10-100 μeV for nanoscale separations, allowing experimental verification.
线性反铁磁体（AFs）支持两种简并的磁振子激发，它们携带相反的自旋极化，通过这种方式，磁振子可以在各种与自旋相关的现象中充当电子。在绝缘铁磁体（F）/AF/F 三层结构中，我们通过计算 AF 中磁振子的热能量来研究通过磁振子介导的层间耦合，其作为 Fs 取向的函数。这种效应表现为层间交换相互作用和垂直磁各向异性；它们都取决于温度和 AF 的厚度。特别是，交换相互作用在低温下表现为反铁磁性，在高温下表现为铁磁性，其大小对于纳米级的分离可以达到 10-100μeV，这使得实验验证成为可能。
