Influence of interfacial Dzyaloshinskii-Moriya interaction on parametric amplification of spin waves in ultrathin magnetic films

Abstract

When the thickness of a ferromagnetic film is reduced to a nanoscale, surface and interface effects start to play more and more important role in the static magnetic properties and magnetization dynamics. One of such effects of a significant current research interest is the interfacial Dzyaloshinskii-Moriya interaction (IDMI) which takes place at the interface of a ferromagnet and a normal metal with large spin-orbit coupling (e.g., Fe-W interface). It has been shown recently, that IDMI could result in the formation of chiral static magnetic structures in ultrathin ferromagnetic films [1-2] or in the non-reciprocity of the spin wave (SW) spectrum in these films [3-4]. In this work it is shown, that the SW nonreciprocity induced by the IDMI could qualitatively change the dynamics of SWs under the influence of parametric pumping, and could significantly improve the characteristics of parametric amplifiers of SW microwave signals.