  The Galactic magnetic field plays an important role in the evolution of the
Galaxy, but its small-scale behaviour is still poorly known. It is also unknown
whether it permeates the halo of the Galaxy or not. By using observations of
pulsars in the halo globular cluster 47 Tucanae, we probed the Galactic
magnetic field at arcsecond scales for the first time and discovered an
unexpected large gradient in the component of the magnetic field parallel to
the line of sight. This gradient is aligned with a direction perpendicular to
the Galactic disk and could be explained by magnetic fields amplified to some
60 {\mu}G within the globular cluster. This scenario supports the existence of
a magnetized outflow that extends from the Galactic disk to the halo and
interacts with the studied globular cluster.
