  We performed detailed conductivity and tunneling mesurements on the
amorphous, magnetically doped material $\alpha$-Gd$_x$Si$_{1-x}$ (GdSi), which
can be driven through the metal-insulator transition by the application of an
external magnetic field. Conductivity increases linearly with field near the
transition and slightly slower on the metallic side. The tunneling conductance,
proportional to the density of states $N(E)$, undergoes a gradual change with
increasing field, from insulating, showing a soft gap at low bias, with a
slightly weaker than parabolic energy dependence, i.e. $N(E) \sim E^c$, $c
\lesssim 2$, towards metallic behavior, with $E^d$, $0.5 \lt d \lt 1$ energy
dependence. The density of states at the Fermi level appears to be zero at low
fields, as in an insulator, while the sample shows already small, but
metal-like conductivity. We suggest a possible explanation to the observed
effect.
