Low temperature ac conductivity of La0.95Sr0.05MnO3.08

The ac conductivity of La0.95Sr0.05MnO3.08 has been measured at temperature s between 20-77 K, and for frequencies up to 100 kHz. A comparison of the m easured ac conductivity sigma(omega) has been made with some of the models of hopping conductivity proposed earlier in the literature. It is observed that in Lao(0.95)Sr(0.05)Mn(3.08) the measured ac conductivity, over the en tire frequency and temperature region, can be explained reasonably well by assuming two contributions sigma(1)(omega) and sigma(2)(omega) to the measu red sigma(omega). The frst, sigma(1)(omega), which dominates at low tempera tures (T < 40 K), may be due to the impurity conduction in small polarons o f ligand holes (L); the second, sigma(2)(omega), which dominates at higher temperatures (T > 40 K), depending on the frequency of measurement, may be due to hopping of small polarons and is responsible for the activated diele ctric loss peak.