Broadband conversion of microwaves into propagating spin waves in patterned magnetic structures

Abstract

We have used time-resolved scanning Kerr microscopy (TRSKM) and micromagnetic simulations to demonstrate that, when driven by spatially uniform microwave field, the edges of patterned magnetic samples represent both efficient and highly tunable sources of propagating spin waves. The excitation is due to the local enhancement of the resonance frequency induced by the non-uniform dynamic demagnetizing field generated by precessing magnetization aligned with the edges. Our findings represent a crucial step forward in the design of nanoscale spin-wave sources for magnonic architectures, and are also highly relevant to the understanding and interpretation of magnetization dynamics driven by spatially-uniform magnetic fields in patterned magnetic samples.

Dynamics of spiral spin waves in magnetic nanopatches: Influence of thickness and shape

“…2(a)), in accordance with the analytical model for spin waves in a Damon-Eshbach configuration from [34], which takes into account the finiteness of the element. This is also consistent with previous results where the edges act as spin wave emitters [12]. In thicker disks ( Fig.…”

Direct observation of coherent magnons with suboptical wavelengths in a single-crystalline ferrimagnetic insulator

“…It has been shown that local magnetic formations such as domain walls [45][46][47], edge bound demagnetizing fields [33,48,49], or vortices [23,24,50] can function as spin wave emitters offering effective "antenna" widths well below 200 nm. A major advantage of this approach is that the devices providing such formations are a lot larger than these effective widths.…”

Magnetic interfaces as sources of coherent spin waves

“…For the same reason, no spin-wave emission is possible if the source term = (14) becomes equal to zero for any other reason. Depending on the problem, the local microwave susceptibility tensorsχ A(B) in the vicinity of the interface can be calculated analytically [23] or from micromagnetic simulations [22,24]. The most efficient emission is expected when the source term is strongest.…”