RESUMEN
The spin torque nano-oscillator (STNO), a nanosize microwave signal generator, have caught the attention of a number of researchers due to its obvious advantages. Recently a chiral bulk material with twisted skyrmion has been discovered in studies with different helicity degrees. In this work, we design a new STNO based on twisted skyrmion existing in free layers of magnetic tunnel junction structure. We first investigate the effect of the magnetic moment of fixed layer on the twisted skyrmion and frequency of STNO. Although the magnetic moment of fixed layer does not affect the state of the twisted skyrmion but affects the precession frequency of STNO. Later, the current, external magnetic field and Dzyaloshinskii-Moriya interaction strength are changed to regulate the oscillation frequency of STNO. Our result may be favorable for the design of new twisted skyrmion-based STNO.
RESUMEN
We investigated the dynamical behaviors of an all-permalloy structured spin-torque nano-oscillator (STNO) composed of a nanostripe with in-plane magneto-anisotropy and a free magnetized nanopillar in the absence of a non-magnetic spacer via a micro-magnetic simulation. It is found the newly-devised STNO exhibits two stable precession modes of magnetization in the nanopillar: out-of-plane precession mode and in-plane precession mode under varying applied DC current densities. The switching between the two modes is generated in a certain current density, depending on geometries of the nanopillar as well as the nanostripe. Given a special nanopillar geometry, both modes demonstrate stable oscillation properties in a certain range of current densities. Pulsed magnetic field can effectively realize transformation of the two modes under application of a proper current density. The realization of synchronous oscillations to significantly enhance the output power is verified in this new type of STNO by etching plenty of nanopillars on the nanostripe to build STNOs array.