  Variable temperature scanning tunneling microscopy/spectroscopy studies on
single crystals and epitaxial thin films of hole-doped manganites, which show
colossal magnetoresistance, have been done. We have investigated the variation
of the density of states, at and near the Fermi energy ($E_f$), as a function
of temperature. Simple calculations have been carried out, to find out the
effect of temperature on the tunneling spectra and extract the variation of
density of states with temperature, from the observed data. We also report
here, atomic resolution images, on the single crystals and larger range images
showing the growth patterns on thin films. Our investigation shows
unambiguously that there is a rapid variation in density of states for
temperatures near the Curie temperature ($T_c$). While for temperatures below
$T_c$, a finite DOS is observed at $E_f$, for temperatures near $T_c$ a hard
gap opens up in the density of states near $E_f$. For temperatures much higher
than $T_c$, this gap most likely gives way to a soft gap. The observed hard gap
for temperatures near $T_c$, is somewhat higher than the transport gap for all
the materials. For different materials, we find that the magnitude of the hard
gap decreases as the $T_c$ of the material increases and eventually, for
materials with a $T_c$ close to 400 K, the value of the gap approaches zero.
