  The magnetotransport properties were studied in hundreds of micrometer length
double-wall carbon nanotubes (DWCNT) bundles. Above 15 K the resistance shows
an ohmic behavior and its temperature dependence is well described using the
variable-range hopping for one-dimensional system. The magnetoresistance is
negative and can be explained using an empirical model based on spin-scattering
processes indicating the existence of magnetic order up to room temperature. At
temperatures between 2 K and 15 K the resistance is non-ohmic and the
current-voltage characteristics reveal the appearance of a potential, which can
be well described by a fluctuation-induced tunneling conduction model. In this
low temperature range and at low enough input current, a positive
magnetoresistance appears - in addition to the negative one - with an
extraordinary hysteresis in field and vanishes at $T \sim 15 $K, suggesting the
existence of a superconducting state. Magnetization results partially support
the existence of both phenomena in the DWCNT bundles.
