Interplay between intra- and inter-nanowires dynamic dipolar interactions in the spin wave band structure of Py/Cu/Py nanowires

Abstract

We have studied both experimentally and theoretically the reprogrammable spin wave band structure in Permalloy(10 nm)/Cu(5 nm)/Permalloy(30 nm) nanowire arrays of width w = 280 nm and inter-wire separation in the range from 80 to 280 nm. We found that, depending on the inter-wire separation, the anti-parallel configuration, where the magnetizations of the two Permalloy layers point in opposite directions, is stabilized over specific magnetic field ranges thus enabling us to directly compare the band structure with that of the parallel alignment. We show that collective spin waves of the Bloch type propagate through the arrays with different magnonic bandwidths as a consequence of the interplay between the intra- and inter-nanowire dynamic dipolar interactions. A detailed understanding, e.g. whether they have a stationary or propagating character, is achieved by considering the phase relation (in-phase or out-of-phase) between the dynamic magnetizations in the two ferromagnetic layers and their average value. This work opens the path to magnetic field-controlled reconfigurable layered magnonic crystals that can be used for future nanoscale magnon spintronic devices.

Applications of nanomagnets as dynamical systems: II

“…Effort has been made to prepare 1D nanomagnet array by step modulated thickness either made of a single material [361] or two different materials [312,362]. In the latter case, the height of the top layer strongly affects the magnonic band structures.…”

Magnonic crystals: towards terahertz frequencies

“…Generally, details of the magnonic band structure of such a system depend on the coupling strength between the stripes. Such a coupling can be tuned either by changing the separation distance between stripes [167] or by changing the width of stripes [168]. The latter one shall also change the frequency and the shape of the intrinsic mode.…”

Engineered Magnetization Dynamics of Magnonic Nanograting Filters

“…Several methods have been implemented to produce the desired spin transmission spectra. Realizing a geometry-driven energy band gap formation allows enabling several prominent features to emerge, such as guided information carrier by periodic arrays of nanostrips [7,8] and width-modulated nanogratings [9][10][11][12]. Besides that spatial periodic variation of saturation magnetization, alternating nanostrips, filters, and phase shifters were investigated with different material classes [8,[13][14][15][16], where Y 3 Fe 5 O 12 (YIG) and permalloy were the common types for MC.…”