We describe the effects of electronic perturbation distributed on nearest neighbor sites to the impurity center in a planar d-wave superconductor, in approximation of circular Fermi surface. Alike the behavior previously reported for point-like perturbation and square Fermi surface, the quasiparticle density of states ρ (ϵ) can display a resonance inside the gap (and very weak features from low symmetry representations of non-local perturbation) and asymptotically vanishes at ϵ→ 0 as ρ∼ϵ/^2ϵ.

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... e local suppression of SC order parameter in this model is found to be somewhat weaker than for an equivalent point-like (non-magnetic) perturbation and much weaker than for a spin-dependent (extended) perturbation.