Full text loading...
(a) Model geometry of indicated dimensions and initial vortex ground state, wherein vortex-core magnetization is upward and in-plane curling magnetization is counter-clockwise. The orange arrow indicates theoscillating magnetic fields. On the right is the m z component profile across the core center. (b) Average m z component, 〈m z〉, over entire nanodisk versus time after application of sinc field. The inset shows the sinc function expressed as with = 50 Oe, = 100 GHz and = 1 ns. (c) Power spectrum obtained from method explained in text. The vertical arrows indicate the eigenfrequencies of the radial-mode spin waves. (d) Plane-view images of spatial distributions of FFT powers for n = 1, 2, and 3 modes obtained at corresponding eigenfrequencies 10.7, 15.2, and 20.7 GHz, respectively, along with profiles across center position.
Snapshot images of temporal evolution of n = 1 radial mode excitation up to vortex-core reversal, with corresponding m z profiles. The field applied was a single harmonic sine-wave field of H 0 = 350 Oe and f H = 10.7 GHz.
(a) Variation of m z component averaged over core region (i.e., averaged over 4 cells) during excitation of n = 1 radial mode up to vortex-core reversal. (b) Temporal variation of each energy density and sum averaged over core region (r ≤ 4 nm). The gray dashed line shows the maximum exchange energy density, = 2.62 × 106 J/m3, obtained during the vortex-core reversal driven by a perpendicular bias static field, ≈ −5.29 kOe. The numbers on the top of the panel in (a) indicate the times at which the snapshot images shown in Fig. 2 were taken. (c) Same as (b), but for time ranges spanning occurrence of switching events.
Phase diagrams of (a) switching events and (b) switching times with respect to H 0 and f H. In (a), the large open circles represent the occurrence of vortex-core-reversal events at the indicated H 0 and f H values. The colors, according to the color bar scale (top), represent the values. The solid curves indicate the threshold fields near the radial-mode eigenfrequencies. In (b), the colors in the vortex-core-reversal region, according to the color bar scale (top), correspond to the switching times.
Article metrics loading...