@article {Saadaoui2009TRSB, title = {Search for time-reversal symmetry breaking order at the (110) interface of YBa$_2$Cu$_3$O$_{7-δ$ using $\beta$NMR}, journal = {Physica B: Condensed Matter}, volume = {404}, number = {5{\textendash}7}, year = {2009}, note = {Proceedings of the Eleventh International Conference on Muon Spin Rotation, Relaxation and Resonance}, pages = {724 - 726}, abstract = {In this paper, we report initial β \{NMR\} measurements seeking the spontaneous magnetic fields associated with a time-reversal symmetry breaking (TRSB) order at the (1\&$\#$xa0;1\&$\#$xa0;0) interface of the high temperature superconductor \{YBa\} 2 Cu 3 O 7 - δ (YBCO). A 2\&$\#$xa0;keV beam of highly spin-polarized Li + 8 was implanted into a thin overlayer of silver sputtered onto an oriented \{YBCO\} film. The \{NMR\} of Li 8 in the Ag layer showed additional broadening with an onset below the superconducting transition temperature T c . This is evidence of spontaneous disordered magnetism which could be associated with \{TRSB\} order.}, keywords = {Time-reversal symmetry breaking}, issn = {0921-4526}, doi = {http://dx.doi.org/10.1016/j.physb.2008.11.188}, url = {http://www.sciencedirect.com/science/article/pii/S0921452608006534}, author = {H. Saadaoui and G.D. Morris and K.H. Chow and M.D. Hossain and C.D.P. Levy and T.J. Parolin and M.R. Pearson and Z. Salman and M. Smadella and Q. Song and D. Wang and P.J. Hentges and L.H. Greene and R.F. Kiefl and W.A. MacFarlane} }