Thermal conductivity of Bi₂Sr₂CaCu₂O₈ in the mixed state

We have investigated ab-plane thermal conductivity in single crystals of Bi₂Sr₂CaCu₂O₈ in the mixed state. We find that the ab-plane thermal conductivity, k{cyrillic}ab, below Tc depends on the magnitude and orientation of the magnetic field. A simple empirical expression was found for k{cyrillic}abHθc), which suggests that electron component of k{cyrillic}ab is responsible for the normal state behavior of the ab-plane thermal conductivity. However, the k{cyrillic} anomaly in the superconducting state is attributed to an increase in its phonon component and a rapid decrease of quasiparticle scattering below Tc.