Magnon junction effect in Y3Fe5O12/CoO/Y3Fe5O12 insulating heterostructures

Applied Physics Letters, Volume 119, Issue 21, November 2021. Magnonics as an emerging frontier of spintronics aims using magnons to deliver information free from electron scattering and as-induced Joule heating. In general, magnon currents can be excited both thermally and electrically in magnetic insulators by applying a current in an adjacent heavy-metal layer. Here, we report another kind of magnon junctions (MJs) composed of [math]/CoO/[math] heterostructures, in which [math] and CoO are, respectively, ferrimagnetic and antiferromagnetic insulators. A temperature gradient can drive a high (low) magnon current via the spin Seebeck effect when the [math] layers in an MJ are configured at the parallel (antiparallel) state, showing a spin valve-like behavior. Electrically injected magnon current could also be controlled by the MJs, contributing to a magnon-mediate nonlocal spin Hall magnetoresistance (SMR). Furthermore, compared with its NiO counterpart, both the magnon junction and magnon-mediate SMR effects can be clearly observed at room temperature for the CoO-based magnon junctions, which can possibly be applied as a building block for room-temperature magnon-based memory or logic devices.