  In this paper, following a stream of investigation on supersymmetric gauge
theories with cosmic string solutions, we contemplate the possibility of
building up a D-and-F term cosmic string by means of a gauge-field mixing in
connection with a U(1) x U(1)'-symmetry. The spontaneous break of both gauge
symmetry and supersymmetry are thoroughly analysed and the fermion zero-modes
are worked out. The role of the gauge-field mixing parameter is elucidated in
connection with the string configuration that comes out. As an application of
the model presented here, we propose the possibility that the supersimetric
cosmic string yield production of fermionic charge carriers that may eject, at
their late stages, particles that subsequently decay to produce cosmic rays of
ultra-high energy. In our work, it turns out that massive supersymmetric
fermionic partners may be produced for a susy breaking scale in the range
10^{11} to 10^{13} GeV, which is compatible with the phenomenology of a
gravitino mass at the TeV scale. We also determine the range of the gauge-field
mixing parameter, \alpha, in connection with the mass scales of the present
model.
