Magnetic ordering in Cr-doped Bi₂Se₃ thin films by Collins-Mcintyre, LJ, Harrison, SE, Schoenherr, P, Steinke, N-J, Kinane, CJ, Charlton, TR, Alba-Veneroa, D, Phusp, A, Kellock, AJ, Parkin, SSP, Harris, JS, Langridge, S, van der Laan, G, Hesjedal, T