Spectroscopically Resolved Imaging of Spin Dynamics in Ferromagnets Using Nitrogen-Vacancy Centers in Diamond

Understanding ferromagnetic dynamics is important for the development of future nanoscale spintronic and magnonic devices. Nitrogen-vacancy centers (NV) in diamond provide us with one of the few tools that has been shown to be capable of both broadband spectroscopy of ferromagnetic resonance$^{1}$ and nanometer scale imaging of magnetic fields$^{2}$. Towards the goal of studying ferromagnetic dynamics at the nanoscale, we report recent results of the local spectroscopy of spin dynamics in ferromagnetic materials using NV centers. We see an especially strong coupling to low frequency excitations such as domains and domain walls, and observe a clear spatial dependence of the excitation of different spin wave modes. \\\\ $^1$C.S. Wolfe, V.P. Bhallamudi, H.L. Wang, C.H. Du, S. Manuilov, R.M. Teeling-Smith, A.J. Berger, R. Adur, F.Y. Yang, and P.C. Hammel, Phys. Rev. B \textbf{89}, 180406(R) (2014) \\ $^2$G. Balasubramanian, I.Y. Chan, R. Kolesov, M. Al-Hmoud, J. Tisler, C. Shin, C. Kim, A. Wojcik, P.R. Hemmer, A. Krueger, T. Hanke, A. Leitenstorfer, R. Bratschitsch, F. Jelezko, and J. Wrachtrup, Nature \textbf{455}, 648 (2008)