Magnon dispersion relations and magnetization profiles. (a) Magnon dispersion relations of the Py/BARC magphonic crystal. Experimental data are denoted by dots and theoretical data by lines, with solid (dotted) lines representing modes with relatively strong (weak) intensities. Measured bandgaps are shown as shaded bands, and Brillouin zone boundaries as vertical-dashed lines. The theoretical branches are labeled M1 to M3 and N1 to N5 (see text). The blue bars around q = 0 indicate calculated frequencies of the confined modes of an isolated Py stripe. (b) Cross section of magnetization profiles of the magnon modes within one Py stripe in a unit cell of the magphonic crystal at q = π/a. The dynamic magnetization vectors are represented by arrows, with their color-coded magnitudes.