A detailed investigation of the magnetic response of YBaCuO grain boundary Josephson junctions has been carried out using both radio-frequency measurements and Scanning SQUID Microscopy. In a nominally zero-field-cooled regime we observed a paramagnetic response at low external fields for 45 degree asymmetric grain boundaries. We argue that the observed phenomenology results from the d-wave order parameter symmetry and depends on Andreev bound states.
Cite
@article{arxiv.cond-mat/0306722,
title = {Paramagnetic effect in YBaCuO grain boundary junctions},
author = {E. Il'ichev and F. Tafuri and M. Grajcar and R. P. J. IJsselsteijn and J. Weber and F. Lombardi and J. R. Kirtley},
journal= {arXiv preprint arXiv:cond-mat/0306722},
year = {2009}
}