A quantitative analysis of the thermoelectric power measurements on composite Al-Ge films

Thermoelectric power (Seebeck coefficient) measurements at room temperature have been made on composite Al-Ge films for aluminum volume fractions ranging from 20% to 100%. The critical metallic concentration φ_c at the metal-insulator transition is about φ_c{reversed tilde equals}55%. These measurements were motivated to test theoretical predictions recently suggested by Bergman and Levy. The electrical conductivity, a variable in their equation, was obtained both by direct measurements and by an effective media equation, while the thermal conductivity was obtained from two different effective media equations. The agreement between the theoretical and experimental results support the correctness both of their theory and the effective media equations used.