  Flux-dominated solar dynamo models, which have demonstrated to be quite
successful in reproducing most of the observed features of the large scale
solar magnetic cycle, generally produce an inappropriate latitudinal
distribution of the toroidal magnetic fields, showing fields of large magnitude
in polar regions where the radial shear has a maximum amplitude. Employing a
kinematic solar dynamo model, we here explore the contribution of both the
radial and the latitudinal shear in the generation of the toroidal magnetic
fields by varying the shape and the thickness of the solar tachocline. We also
explore the effects of the diffusivity profile of the convective zone. We find
that the latitudinal component is always dominant over the radial component at
producing toroidal field amplification. These results are very sensitive to the
adopted diffusivity profile, specially in the inner convection zone. A diagram
of the toroidal field at a latitude of 60 degrees versus the diffusivity at the
convection layer for different values of the tachocline width has revealed that
these fields are mainly eliminated for tachoclines with width d_1>0.08 Ro, for
a restric range of diffusivites; or for d_1<0.02 and almost any value of eta_c
in the appropriate solar range. For intermediate values of d_1=0.04Ro-0.06Ro,
strong toroidal fields should survive at high latitudes in the butterfly
diagram and those values are therefore not suitable.
