Collective mode splitting in hybrid heterostructures

Abstract

We report on a drastic change of the Ni collective magnetization dynamics when incorporated into a Ni/V2O3 heterostructure. Two, unexpected, well-defined Ni ferromagnetic resonance (FMR) modes are observed in the coexistence region of the first-order V2O3 structural phase transition (SPT). The phase coexistence across the V2O3 SPT can explain the presence of the two resonance fields but not their anticrossing and large linewidth broadenings. Our results imply a strong coupling between the lattice dynamics of the strongly correlated oxide (V2O3) and the magnon modes of the ferromagnet (Ni) in this hybrid. This and additional experiments on Ni grown on SrTiO3, a prototypical second-order phase transition oxide, imply that these effects require the presence of first-order transitions in the oxides.