Low-temperature ferromagnetism in a new diluted magnetic semiconductor Bi$_{2-x}$Fe$_x$Te$_3$

Single crystals of a new diluted magnetic semiconductor Bi$_{2-x}$Fe$_x$Te$_3$ ($0\leq x\leq0.08$) were grown. For all crystals, the transition into a ferromagnetic state with easy axis parallel to the $C_3$ axis was observed at temperature $T_c$ increasing with iron concentration and reaching 12 K at $x=0.08$. An increase in the Seebeck coefficient, anomalous Hall effect, and resistivity jump at $T=T_c$ were also observed. The frequency of the de Haas–van Alphen oscillations decreases with increasing $x$, indicating the donor properties of Fe.