  The influence of He+ ion irradiation on the transport and magnetic properties
of epitaxial layers of a diluted magnetic semiconductor (DMS) (In,Fe)Sb, a
two-phase (In,Fe)Sb composite and a nominally undoped InSb semiconductor has
been investigated. In all layers, a conductivity type conversion from the
initial n-type to the ptype has been found. The ion fluence at which the
conversion occurs depends on the Fe concentration in the InSb matrix.
Magnetotransport properties of the two-phase (In,Fe)Sb layer are strongly
affected by ferromagnetic Fe inclusions. An influence of the number of
electrically active radiation defects on the magnetic properties of the
single-phase In0.75Fe0.25Sb DMS has been found. At the same time, the results
show that the magnetic properties of the In0.75Fe0.25Sb DMS are quite resistant
to significant changes of the charge carrier concentration and the Fermi level
position. The results confirm a weak interrelation between the ferromagnetism
and the charge carrier concentration in (In,Fe)Sb.
