The infrared Hall effect in YBCO: Temperature and frequency dependence of Hall scattering

We measure the Hall angle, theta(H), in YBCO films in the far- and mid-infr ared to determine the temperature and frequency dependence of the Hall scat tering. Using novel modulation techniques we measure both the Faraday rotat ion and ellipticity induced by these films in high magnetic fields to deduc e the complex conductivity tensor. We observe a strong temperature dependen ce of the mid-infrared Hall conductivity in sharp contrast to the weak depe ndence of the longitudinal conductivity. By fitting the frequency dependent normal state Hall angle to a Lorentzian theta(H)(omega) = omega(H)/(gamma( H) - i omega) we find the Hall frequency, omega(H), is nearly independent o f temperature. The Hall scattering rate, gamma(H), is consistent with gamma (H) approximate to T-2 up to 200 K and is remarkably independent of IR freq uency suggesting non-Fermi liquid behavior.