  We investigate multiple Fano, comblike scattering resonances in
single-layered, concentric core-shell nanoparticles composed of magnetic
materials. Using the Lorenz-Mie theory, we derive, in the long-wavelength
limit, an analytical condition for the occurrence of comblike resonances in the
single scattering by coated spheres. This condition establishes that comblike
scattering response uniquely depends on material parameters and thickness of
the shell, provided that it is magnetic and thin compared to the scatterer
radius. We also demonstrate that comblike scattering response shows up beyond
the long-wavelength limit and it is robust against absorption. Since multiple
Fano resonances are shown to depend explicitly on the magnetic permeability of
the shell, we argue that both the position and profile of the comblike,
morphology-dependent resonances could be externally tuned by exploiting the
properties of engineered magnetic materials.
