We have developed a new system to measure the microwave flux-flow Hall effect [1]. The new method enables us to measure microwave Hall effect of materials with high conductivity at low temperatures. Using the system, we investigate the flux flow Hall effect of high T_c cuprate superconductor, Bi₂Sr₂CaCu₂O_y. In the vortex state, with increasing magnetic field, Hall angle, tanq, approaches to a constant value at each temperature. We obtained ω₀τ ≈2-3 in the low temperature limit (ω₀ and τ are the level spacing of quasiparticle in the vortex core and the quasiparticle scattering time in the vortex core, respectively), which is larger than the estimated value by the effective viscous drag coefficient η^*. In this talk, we will discuss the implication of the results.
[1] R. Ogawa, et. al., APS march meeting 2020 (preceding talk).