The Infrared Hall Effect in YBCO: Temperature and Frequency Dependence of Hall Scattering

We measure the Hall angle, θH, in YBCO films in the far- and mid-infrared to determine the temperature and frequency dependence of the Hall scattering. Using novel modulation techniques we measure both the Faraday rotation and ellipticity induced by these films in high magnetic fields to deduce the complex conductivity tensor. We observe a strong temperature dependence of the mid-infrared Hall conductivity in sharp contrast to the weak dependence of the longitudinal conductivity. By fitting the frequency dependent normal state Hall angle to a Lorentzian θH(ω) = ωH/(γH - iω) we find the Hall frequency, ωH, is nearly independent of temperature. The Hall scattering rate, γH, is consistent with γH ≈ T² up to 200 K and is remarkably independent of IR frequency suggesting non-Fermi liquid behavior.