Paramagnetic effect in YBaCuO grain boundary junctions
E.Il'ichev, F. Tafuri, M. Grajcar, R.P.J. IJsselsteijn, J. Weber, F. Lombardi, J.R. Kirtley
Abstract
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.