  We propose a one-dimensional model consisting of a chain with a t-J
Hamiltonian coupled to a Heisenberg chain in a frustrated geometry to describe
the appearance of the ferromagnetic phase which has been experimentally
observed in vanadate nanotubes. This model contains a mechanism of frustration
suppressed by doping suggested by L. Krusin-Elbaum, et al. [Nature 431, 672
(2004)]. We study, using numerical techniques in small clusters, the relation
between magnetic order and transport properties in the proposed model, and we
perform a detailed comparison of the physical properties of this model with
those of the ferromagnetic Kondo lattice model. For this comparison, a number
of results for the latter model, obtained using the same numerical techniques,
will be provided to complement those results already available in the
literature. We conclude that it does not appear to be a true ferromagnetic
order in the proposed model, but rather an incommensurate ferrimagnetic one,
and contrary to what happens in the ferromagnetic Kondo lattice model,
electronic transport is somewhat suppressed by this ferrimagnetic order.

Strongly Correlated Electrons