Half-integer flux quantum effect in tricrystal Bi2Sr2CaCu2O8+δ J. R. Kirtley, C. C. Tsuei, H. Raffy, Z. Z. Li, A. Gupta, J. Z. Sun and S. Megtert Europhys. Lett., 36 9 (1996) 707-712 Published online: 01 September 2002 DOI: 10.1209/epl/i1996-00291-y