Brillouin light scattering studies of confined spin waves: linear and nonlinear confinement

This review is devoted to both the experimental and theoretical aspects of lateral confinement effects observed for spin waves, with the wavevector in the 102–106 cm−1 range, where the magnetic dipole interaction plays the most important role. The Brillouin light scattering (BLS) technique is a powerful tool for the investigation of these effects. In addition to a high sensitivity, which is characteristic for a standard BLS system, we have extended the method to achieve high lateral spatial (30–50 μm), as well as temporal (1–2 ns) resolution. This is central for the studies summarized in the review. Two representative experimental situations are reviewed: (1) Spin wave confinement in micron size laterally pattered structures (regular arrays of magnetic dots and wires). We focus on the quantization of spin wave wavevectors due to the lateral boundaries of a dot or a wire, and the influence of the static and dynamic coupling between islands. (2) Spatial, temporal and spatio-temporal confinement of linear and nonlinear spin waves in magnetic ferrite films. The formation, propagation, and collision of envelope solitons and their two-dimensional analogs (spin wave bullets) are analyzed. Both analytical and numerical models for spin waves in quasi-one-dimensional waveguides and in wide films are discussed.