Magnetotransport parameters of La0.67Ca0.33MnO3 films grown on neodymium gallate substrates

Weakly mechanically stressed 40-nm-thick La0.67Ca0.33MnO3 films have been grown coherently on a (001)NdGaO3 substrate by laser evaporation. The electrical resistivity ρ of the La0.67Ca0.33MnO3 film reaches a maximum at a temperature TC ≈ 255 K. At temperatures below 0.6TC, the temperature dependences of ρ are well approximated by the relation ρ = ρdef + C1T2 + C2T4.5, in which the first term on the right-hand side accounts for the contribution of structural defects to electrical resistivity, and the second and third terms stand for those of the electron-electron and electron-magnon interactions, respectively. The parameters ρdef ≈ 1 x 10−4 Ω cm and C1 ≈ 7.7 × 10−9 Ω cm K−2 do not depend on temperature and magnetic field H. The coefficient C2 decreases with increasing H to reach about 4.9 × 10−15 Ω cm K−4.5 at μ0H = 14 T.