  The effects of dc excitation current on the current-voltage curves of
polycrystalline samples of Nd0.5Ca0.5Mn0.96Cr0.04O3 were investigated. The
experimental results show that an abrupt jump of the voltage is concomitant
with a huge increase in the temperature of the sample. A simple model and
estimates for Joule self-heating effects support the experimental data.
Moreover, the data strongly suggest that both the current localization in the
metallic paths and local Joule self-heating effects are essential ingredients
to understand the current-induced phase transition in phase-separated
manganites.
