  Interfacing superconductors with strongly spin-polarized magnetic materials
opens the possibility to discover new spintronic devices in which spin-triplet
Cooper pairs play a key role. Motivated by the recent derivation of
spin-polarized quasiclassical boundary conditions capable of describing such a
scenario in the diffusive limit, we consider the emergent physics in hybrid
structures comprised of a conventional s-wave superconductor (e.g. Nb, Al) and
either strongly spin-polarized ferromagnetic insulators (e.g. EuO, GdN) or
halfmetallic ferromagnets (e.g. CrO2, LCMO). In contrast to most previous
works, we focus on how the superconductor itself is influenced by the proximity
effect, and how the generated triplet Cooper pairs manifest themselves in the
self-consistently computed density of states (DOS) and the superconducting
critical temperature Tc. We provide a comprehensive treatment of how the
superconductor and its properties are affected by the triplet pairs,
demonstrating that our theory can reproduce the recent observation of an
unusually large zero-energy peak in a superconductor interfaced with a
half-metal, which even exceeds the normal-state DOS. We also discuss the recent
observation of a large superconducting spin-valve effect with a Tc change ~1K
in superconductor/half-metal structures, in which case our results indicate
that the experiment cannot be explained fully by a long-ranged triplet
proximity effect.
