Modulation the phase of propagating spin wave in waveguide by spin-polarized current

摘要

In this work, we propose a new ways to control the phase shift of propagating spin waves by applying a local spin-polarized current on waveguide, whose schematic is shown in Figure 1(a) . The length, width and thickness of stripe are L= 1500nm, w=40nm, h=5nm . A thin nonmagnetic spacer is placed between the magnetic stripe and pinned magnetic layer with width wp = 10nm . Applied DC current is polarized through the pinned magnetic layer . The direction of spin-polarized current is perpendicular to the film of magnetic stripe . An external magnetic field is applied along the x-axis . An AC field is applied parallel to the z-axis to excite backward-volume spin waves . The dispersions of spin waves in the waveguide were simulated by micromagnetic package OOMMF, using the Landau-Lifshitz-Gilbet (LLG) equation with the Slonczewski-Berger spin torque term . A series of spin-polarized current with different densities were applied through the magnetic stripe . The simulation results are shown in Figure 1(b) . We can see that the phase shift increases with the increasing of spin-polarized current in a certain range . The phase shift can reach about 0 .3π when spin-polarized current density is 12 .5×10A/m. When three pinned magnetic layers are fabricated under the magnetic stripe, a phase shift of about π can be reached . The ways can be used in a Mach-Zender-type interferometer to fulfill logic NOT gates, the interference results of spin waves are shown in Figure 2 .