  Here, we present an electrical transport study in single crystals of
LaFe$_{0.92}$Co$_{0.08}$AsO ($T_c \simeq 9.1$ K) under high magnetic fields. In
contrast to most of the previously reported Fe based superconductors, and
despite its relatively low $T_c$, LaFe$_{1-x}$Co$_x$AsO shows a superconducting
anisotropy which is comparable to those seen for instance in the cuprates or
$\gamma_H = H_{c2}^{ab}/H_{c2}^{c} = m_c/m_{ab} \simeq 9$, where $m_c/m_{ab}$
is the effective mass anisotropy. Although, in the present case and as in all
Fe based superconductors, $\gamma \rightarrow 1$ as $T \rightarrow 0$. Under
the application of an external field, we also observe a remarkable broadening
of the superconducting transition particularly for fields applied along the
inter-planar direction. Both observations indicate that the low dimensionality
of LaFe$_{1-x}$Co$_x$AsO is likely to lead to a more complex vortex
phase-diagram when compared to the other Fe arsenides and consequently, to a
pronounced dissipation associated with the movement of vortices in a possible
vortex liquid phase. When compared to, for instance, F-doped compounds
pertaining to same family, we obtain rather small activation energies for the
motion of vortices. This suggests that the disorder introduced by doping
LaFeAsO with F is more effective in pinning the vortices than alloying it with
Co.
