Vertical dynamic spin-wave mode coupling in a hybrid artificial spin-ice film underlayer system

As the carbon footprint from traditional complementary-metal-oxide-semi-conductor (CMOS) circuits continues to increase, it is imperative to find alternative, more efficient computational architectures. Magnonic systems based on the elementary quanta of spin waves - magnons, offer a potential solution. However, before creating efficient magnonic computing elements, we must understand how to effectively control magnons at the nanoscale. This can be achieved by nanostructured magnetic metamaterials known as artificial spin ice (ASI). ASI is engineered by arranging nanomagnets on periodic or aperiodic lattices. ASI possesses rich microstates that can be easily reconfigured making them attractive candidates for magnonic computing¹.

Here, we couple a square ASI structure made of CoFeB stadium-shaped nanoelements to a continuous NiFe film underlayer to understand how the presence of the ASI affects the spin-wave properties in the film underlayer. We conduct Brillouin light scattering spectroscopy on thermal spin waves as a function of the magnetic field where the field is applied along the symmetry direction of the ASI network. Investigating these field-dependent dynamics resulting from the interplay between the layers and the emerging interlayer hybridization unveils that the ASI lattice facilitates vertical dynamics in the film layer. In particular, our results show that nanometric control of propagating spin waves can be achieved by harnessing dynamic mode coupling in the vertical, i.e., the out-of-plane direction of carefully engineered magnonic structures^2,3.

References:

[1] Gliga, Iacocca, and Heinonen, APL Materials, 8(4), (2020).

[2] Montoncello, Kaffash, Carfagno, Doty, Gubbiotti, and Jungfleisch, J. Appl. Phys. , 133(8), (2023).

[3] Negrello, Montoncello, Kaffash, Jungfleisch, and Gubbiotti, APL Materials 10, 091115 (2022).