The thermal conductivity kappa (H, T) of Hg0.9Tl0.2Ba2Ca2Cu3O8+delta superc
onductor with a transition temperature of 128 K has been measured between 7
-20 K and in magnetic fields of 0-6 Tesla. kappa (H, T) of the sample incre
ases monotonically with increasing temperature in all investigated fields.
It is significantly reduced upon the application of the magnetic field and
finally reaches a field-independent value. The effects of magnetic field on
the thermal conductivity for Hg0.9Tl0.2Ba2Ca2Cu3O8+delta superconductor ca
n be attributed to an additional thermal resistivity due to the scattering
of the normal electrons by vortices.