Figure 1. Temperature dependence of resistivity for (Pb_0.975Ge_0.025Te)_1-z(Pb_0.96Ge_0.04Se)_z samples. 1, z=0; 2, z=0.42; 3, z=0.57; 4, z=0.67; 5, z=0.77; 6, z=0.86; 7, z=0.94; 8, z=1 /12/. The curves were arbitrary shifted along vertical axis. The arrows show the direction of temperature change during recording the curves.