In-Plane Magnon Valve Effect in Magnetic Insulator/Heavy Metal/ Magnetic Insulator Device

Abstract

We propose an in-plane magnon valve (MV), a sandwich structure composed of ferromagnetic insulator/heavy metal/ferromagnetic insulator (MI/HM/MI). When the magnetizations of the two MI layers are parallel, the longitudinal conductance in the HM layer is greater than that in the antiparallel state according to the magnetic proximity effect, termed as the in-plane magnon valve effect. We investigate the dependence of MV ratio (MVR), which is the relative change in longitudinal conductance between the parallel and antiparallel MV states, on the difference in electronic structure between magnetized and non-magnetized metal atoms, revealing that MVR can reach 100%. Additionally, the dependence of MVR on the thickness of metal layer is analyzed, revealing an exponential decrease with increasing thickness. Then we investigate the dependence of HM layer conductance on the relative angle between the magnetizations of two MI layers, illustrating the potential of MV as a magneto-sensitive magnonic sensor. We also investigate the effect of Joule heating on the measurement signal based on the spin Seebeck effect. Two designed configurations are proposed according to whether the electron current is parallel or perpendicular to the magnetization of the MI layer. In the parallel configuration, the transverse voltage differs between the parallel and antiparallel MV states. While in the perpendicular configuration, the longitudinal resistance differs. Quantitative numerical results indicate the feasibility of detecting a voltage signal using the first configuration in experiments. Our work contributes valuable insights for the design, development and integration of magnon devices