  We use scanning tunneling microscopy (STM) to study magnetic Fe impurities
intentionally doped into the high-temperature superconductor
Bi$_{2}$Sr$_{2}$Ca$_{2}$CuO$_{8+\delta}$. Our spectroscopic measurements reveal
that Fe impurities introduce low-lying resonances in the density of states at
\Omega$_{1}$ $\approx$ 4meV and \Omega$_{2}$ $\approx$ 15 meV allowing us to
determine that, despite having a large magnetic moment, potential scattering of
quasiparticles by Fe impurities dominates magnetic scattering. In addition,
using high-resolution spatial characterizations of the local density of states
near and away from Fe impurities, we detail the spatial extent of impurity
affected regions as well as provide a local view of impurity-induced effects on
the superconducting and pseudogap states. Our studies of Fe impurities, when
combined with a reinterpretation of earlier STM work in the context of a
two-gap scenario, allow us to present a unified view of the atomic-scale
effects of elemental impurities on the pseudogap and superconducting states in
hole-doped cuprates; this may help resolve a previously assumed dichotomy
between the effects of magnetic and non-magnetic impurities in these materials.
