  Magnetoresistive properties of granular Bi-based HTSC with trapped magnetic
fields are investigated in the temperature region near superconducting
transition . The effect of trapped field and transport current values and
orientations on the field dependence of magnetoresistance is studied. It is
found that for the magnetic field parallel and the current perpendicular to
trapping inducing field the field dependence of magnetoresistance is
nonmonotonic and magnetoresistance turns out to be negative for small fields.
The magnetoresistance sign inversion field increases roughly linear with the
trapped magnetic field and slightly decrease with transport current. The
results are explained in the framework of model of magnetic flux trapping in
granules or superconducting loops embedded in weak links matrix.
