We report on a diluted magnetic semiconductor based on the Sb 2 Te 3 tetradymite structure doped with very low concentrations of vanadium ͑1-3 at. %͒. The anomalous transport behavior and robust magnetic hysteresis loops observed in magnetotransport and magnetic measurements are experimental manifestations of the ferromagnetic state in these materials. The p-d exchange between holes and vanadium 3d spins is estimated from the behavior of the magnetoresistance. A Curie temperature of at least 22 K is observed for Sb 1.97 V 0.03 Te 3 . This discovery offers possibilities for exploring magnetic properties of other tetradymite structure semiconductors doped with a wide range of 3d transition metals.

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We report on magnetic and electrical transport properties of Sb 2-x Cr x Te 3 single crystals with 0 ≤ x ≤ 0.095 over temperatures from 2 K to 300 K. A ferromagnetic state develops in these crystals at low temperatures with Curie temperatures that are proportional to x (for x > 0.014), attaining a maximum value of 20 K for x = 0.095. Hysteresis below T C for applied field parallel to the c-axis is observed in both magnetization and Hall effect measurements. Magnetic as well as transport data indicate that Cr takes the 3+ (3d 3 ) valence state, substituting for antimony in the host lattice structure, and does not significantly affect the background hole concentration. Analysis of the anomalous Hall effect reveals that skew scattering is responsible for its presence. These results broaden the scope of ferromagnetism in the V 2 -VI 3 diluted magnetic semiconductors (DMS) and in ferromagnetic DMS structures generally.