Coexistence of cluster spin glass and superconductivity in Ba(Fe(1-x)Co(x))2As2 for 0.060≤x≤0.071. - Dioguardi AP; Crocker J; Shockley AC; Lin CH; Shirer KR; Nisson DM; Lawson MM; apRoberts-Warren N; Canfield PC; Bud'ko SL; Ran S; Curro NJ (Physical review letters, 2013)