  Visible CW (continuous wave) -laser heating effects on the bulk
superconductors CeFeAsO0.65F0.35 and MgB2 with 1.5 mm thickness have been
investigated by measuring the temperature dependence of electrical resistivity.
Each compound shows a critical-temperature Tc reduction with increasing fluence
rate. At the normal state, a parallel circuit model based on the Fourier's law
can well reproduce the temperature dependence of electrical resistivity of
illuminated sample. On the other hand, the predicted temperature-rise due to
the laser heating in the superconducting state is much smaller than the
observed Tc-reduction. A temperature gradient of a few K across the sample
thickness easily triggers the destruction of bulk superconductivity.
Furthermore we have found a slight Tc-enhancement in CeFeAsO0.65F0.35 after a
rather high fluence-rate irradiation.
