  A model combining self-consistent mean-field and shell-model techniques is
used to study the competition between particle like and proton-neutron pairing
correlations in fp-shell even-even self-conjugate nuclei. Results obtained
using constant two-body pairing interactions as well as more sophisticated
interactions are presented and discussed. The standard BCS calculations are
systematically compared with more refined approaches including correlation
effects beyond the independent quasi-particle approach. The competition between
proton-neutron correlations in the isoscalar and isovector channels is also
analyzed, as well as their dependence on the deformation properties. Besides
the expected role of the spin-orbit interaction and particle number
conservation, it is shown that deformation leads to a reduction of the pairing
correlations. This reduction originates from the change of the single-particle
spectrum and from a quenching of the residual pairing matrix elements. The
competition between isoscalar and isovector pairing in the deuteron transfer is
finally addressed. Although a strong dependence the isovector pairing
correlations with respect to nuclear deformation is observed, they always
dominate over the isoscalar ones.
