Temperature Dependence of YIG Magnon Polaritons from 5 Kelvin to Room Temperature

In information technology research, the spin wave-based approach is promising for new applications such as data storage. A spin wave results from a collective spin excitation with the associated quanta called ‘magnon’. Experimentally, we interface magnons with microwave cavities to investigate dynamics within the magnetic system. Magnonic elements are strongly coupled to a photon resonator, resulting in hybridized magnon-resonator states, i.e. magnon polaritons. Our experimental apparatus allows for the resonant coupling of spin waves in a magnetic bulk or thin film to either a microwave cavity or a coplanar waveguide in the strong coupling regime [1, 2]. We present here a temperature dependent spectroscopic study of magnon polariton states from 5 K to 290 K. A millimetre sized YIG sphere is placed in the 6.5 GHz bright mode of a re-entrant cavity [3]. Specifically, temperature dependent features of the strongly coupled system such as the coupling strength g and linewidth, possibly governed by rare earth impurity scattering, of the Kittel mode are discussed [4].
[1] Tabuchi et al., PRL 113 (2014)
[2] Zhang et al., PRL 113 (2014)
[3] Goryachev et al., PRL 2 (2014)
[4] Boventer et al., in prep.