Carrier dependent ferromagnetism in chromium doped topological insulator Cry(BixSb1−x)2−yTe3

To understand the mechanism of ferromagnetism in topological insulator, we studied the structural, magnetic and transport characters of Cry(BixSb1−x)2−yTe3 single crystals. The Curie temperature TC, which is determined from magnetization and anomalous Hall effect (AHE) measurements by Arrott plots, is found to be proportional to yCr⁎p1/3, where p is the hole density. This fact supports a scenario of Ruderman-Kittel-Kasuya-Yoshida (RKKY) interaction with mean-field approximation.