Breathing vibrations of a Néel wall

One may sometimes regard a 180° Néel wall in a cubic ferromagnet as composed of two 90° subwalls or solitons. A spectrum of field-dependent natural frequencies for symmetric breathing of the subwall pair is derived from the Landau–Lifshitz equations in the limit of large uniaxial growth anisotropy and small spontaneous magnetization. The possibility of their excitation in the absence or presence of a Bloch line is discussed. Application to a garnet film of known characteristics predicts externally excitable modes with resonant frequencies near 2 GHz.