Low loss spin wave resonances in organic-based ferrimagnet vanadium   tetracyanoethylene thin films
  We experimentally demonstrate high quality factor spin wave resonances in an encapsulated thin film of the organic-based ferrimagnet vanadium tetracyanoethylene (V[TCNE]$_\textit{x~2}$) coated on an a-plane sapphire substrate by low temperature chemical vapor deposition. The thickness standing wave modes are observed in a broad frequency range (1 GHz ~ 5 GHz) with high quality factor exceeding 3,200 in ambient air at room temperature, rivaling those of inorganic magnetic materials. The exchange constant of V[TCNE]$_\textit{x~2}$, a crucial material parameter for future study and device design of the V[TCNE]$_\textit{x~2}$, is extracted from the measurement with a value of $(4.61\pm 0.35)\times 10^{-16} \mathrm{\: m^{2}}$. Our result establishes the feasibility of using organic-based materials for building hybrid magnonic devices and circuits. 
Na Zhu, Xufeng Zhang, I.H. Froning, Michael E. Flatt\'e, E.   Johnston-Halperin, and Hong X. Tang
cond-mat.mes-hall