Fig. 1: Magnetic fingerprints of V and Cr impurities in (Bi,Sb)2Te3.

XAS (upper panels) and XMCD (lower panels) spectra of a V0.1(Bi0.32Sb0.68)1.9Te3 and b Cr0.1(Bi0.1Sb0.9)1.9Te3 thin films, respectively, at the V and Cr L2,3 edges, taken at temperatures above (hollow circles) and below (full circles) TC. The contribution of the Te M4,5 edges to the Cr L2,3 spectrum is pointed out by the arrows in b. The XMCD spectra (black circles) were measured in the remanent state, at 5 K, demonstrating a FM state for both systems. The small dip in the pre-edge of the Cr L3 XMCD is attributed to the induced magnetic moment in the Te atoms.