narrow gap, p-type semiconductors

Ge_1–xMn_xTe:
Cochrane et al., PRB 9, 3013 (1974)

x = 0.01 T_c = 2.3 K
… …
x = 0.50 T_c = 167 K

good Mn solubility, highly p-doped,
a metal at high x

(Pb,Mn)Te: low hole concentration, no ferromagnetism, spin glass?

(Pb,Sn,Mn)Te: Story et al., PRL 56, 777 (1986)
magnetic interaction is sensitive to hole concentration and long ranged