Absence of spin gap in the superconducting ladder compound Sr_2Ca_{12}Cu_{24}O_{41}

H. Mayaffre, P. Auban-Senzier, D. Jérome +5

Transport and 63^Cu-NMR, Knight shift and T_1, measurements performed on the two-leg spin ladders of Sr_2Ca_{12}Cu_{24}O_{41} single crystals show a collapse of the gap in ladder s…