Finite-size effects in arrays of permalloy square dots

We report a Brillouin light scattering study of spin waves in arrays of permalloy micrometer-size square dots. The retro-scattered spectra under an in-plane applied magnetic field H were performed at various angles of incidence θ, thus allowing one to observe the influence of the modulus (4π/λ) sin θ of the effectively transferred surface wave-vector: the measured frequencies of the magnetic lines are not θ dependent, in contrast with their intensities. The discretization of the frequencies, related to a lateral quantization of a pseudo wave-vector and the variation of the scattered intensities versus θ are discussed within a frame that we have previously developed in the case of arrays of permalloy wires.