Can one think of a Cooper pair tunnelling into a normal metal and "breaking up" into two electrons? I call this Andreev reflection in reverse if the hole excitation is regarded as an electron travelling the other direction. Specifically, I'm trying to understand how Andreev reflection is related to Cooper pairs diffusing into a ferromagnet. Ryazanov et al. in SFS pi-junctions (2004) describes how Andreev reflection relates to the non-zero center of mass momentum obtained by a Cooper pair as it enters the ferromagnet. This explanation is guided by an Andreev account where since the incident electron excitation (I'm not totally sure why it's an electron excitation and not just an electron) and reflected hole excitation (same concern about the use of "excitation") have the same energy, but one's energy is lowered and one raised due to their different spins and the exchange field, their kinetic energies change. So I wonder if I'm overstepping my bounds in thinking that Andreev reflection "in reverse" explains the energetics.