Triplet Andreev reflection off a domain wall in a lateral geometry

We find that geometry is an important ingredient in modeling the triplet Andreev reflection amplitude at the interface between a half-metal and an s-wave superconductor. Considering a domain wall as a source of spin-rotation symmetry breaking we find that while in a serial geometry the Andreev reflection amplitude vanishes at the Fermi energy, it remains finite if the contact is made in a lateral fashion. In addition, if the half metal is a thin film, rather than an extended magnet, the amplitude is enhanced by a factor $l_{\rm d}/d$, where $l_{\rm d}$ is the width of the domain wall and $d$ the film thickness. We conclude that in a lateral geometry, domain walls can be an effective source of the triplet proximity effect.