  We study the current-voltage characteristics of Fe(Se,Te) thin films
deposited on CaF$_2$ substrates in form of nanostrips (width $w\sim\lambda$,
$\lambda$ the London penetration length). In view of a possible application of
these materials to superconductive electronics and micro-electronics we focus
on transport properties in small magnetic field, the one generated by the bias
current. From the characteristics taken at different temperatures we derive
estimates for the pinning potential $U$ and the pinning potential range
$\delta$. Since the sample lines are very narrow, the classical creep flow
model provides a sufficiently accurate interpretation of the data only when the
attractive interaction between magnetic flux lines of opposite sign is taken
into account. The observed voltages and the induced detriment of the critical
current of the nanostrips are compatible with the presence of few tens of
magnetic field lines at the equilibrium and a strongly inhomogeneous current
density distribution. In particular, we argue that the sharp corners defining
the bridge geometry represent points of easy magnetic flux lines injection. The
results are relevant for creep flow analysis in superconducting Fe(Se,Te)
nanostrips.
