Percolation conductivity of single-crystal manganite Pr1 − x Sr x MnO3 (x = 0.22; 0.24) in the phase-separation state

Abstract

This paper presents an experimental study of the temperature dependences of the electrical resistivity, thermopower, and magnetoresistance of single-crystal manganite Pr1 − xSrxMnO3 (x = 0.22, 0.24). The results obtained have been analyzed in terms of the theory of hopping electrical conductivity of manganites in the phase-separation state and the main postulates of percolation theory. In the 2–400-K interval, hopping conductivity with temperature-dependent activation energy has been observed. Near the Curie temperature, the monotonic exponential growth of electrical resistivity with decreasing temperature becomes distorted by formation of finite metallic clusters. For T ≤ 36 K, the conductivity of Pr0.8Sr0.22MnO3 follows the Mott law.