According to XRD the alloys Mn15Bi34Te51 and La15Bi34Te51 were formed after ball milling for 150 h and 100 h, respectively. Nanostructured La15Bi34Te51 resulted from extending the ball milling time to 150 h, It is suggested that the addition of La may refine the grain size and help to promote amorphism in Bi2Te3 based alloys. Further detailed XRD analysis of La15Bi34Te51 alloys suggests that the La atoms may intercalate between the Te Te layers of the Bi2Te3 layer structure. The Seeback coefficient measurements on the La15Bi34Te51 alloys indicates that the carrier scattering mechanism changes when the grain sizes are decreased to a few nanometers leading to a dramatic increase in the Seeback coefficient.