Measurements of the transverse (k_{xy}) and longitudinal (k_{xx}) thermal conductivity in high magnetic fields are used to separate the quasiparticle thermal conductivity (k_{xx}^{el}) of the CuO_2-planes from the phononic thermal conductivity in YBa_2Cu_3O_{7-\delta}. k_{xx}^{el} is found to display a pronounced maximum below T_c. Our data analysis reveals distinct transport (\tau) and Hall (\tau_H) relaxation times below T_c: Whereas \tau is strongly enhanced, \tau_H follows the same temperature dependence as above T_c.
@article{arxiv.cond-mat/9809295,
title = {Separation of Quasiparticle and Phononic Heat Currents in YBCO},
author = {B. Zeini and A. Freimuth and B. Büchner and R. Gross and A. P. Kampf and M. Kläser and G. Müller-Vogt},
journal= {arXiv preprint arXiv:cond-mat/9809295},
year = {2009}
}