We study the Josephson transport through ferromagnetic insulators (FIs) by taking into account its band structure explicitly. In the case of the fully polarized FIs (FPFIs), we found the formation of a pi-junction and an atomic-scale 0-pi transition induced by increasing the FI thickness. More remarkably, in the Josephson junction through spin-filter materials such as Eu chalcogenides, the orbital hybridization between the conduction d and the localized f electron gives rise to the pi-junction behavior. Such FI-based pi-junctions can be used to implement highly-coherent solid-state quantum bits.
@article{arxiv.1004.0757,
title = {Theory of Josephson transport through spintronics nano-structure},
author = {Shiro Kawabata and Yasuhiro Asano and Yukio Tanaka and Satoshi Kashiwaya},
journal= {arXiv preprint arXiv:1004.0757},
year = {2010}
}