Amplitude representation of Landau-Lifshitz equation and its application to ferromagnetic films

In this article we develop a systematic approach to the solution of the Landau-Lifshitz equation in terms of the magnon wave function ψ (r) and apply it to physical phenomena in a thin ferromagnetic film. In this article we represent the modern state of art for the properties of ferromagnetic films and the pumping-induced Bose-Einstein condensation of magnons in them at room temperature. It can be considered as a review on basic principles and the recent advances in the field.