Peak resistance temperature and low temperature resistivity in thin film La_(1-x) Ca_x Mn O₃ mixtures for x <= 1/3

The electrical resistivity of La$_{1-x}$Ca$_{x}$MnO$_{3}$ thin films grown on (001) NdGaO$_{3}$ and (100) SrTiO$_{3}$ substrates by off-axis sputtering has been studied as a function of the Calcium doping level. The samples have very narrow rocking curves and excellent in plane registry with the substrate. A strong correlation between the peak resistance temperature and the polaronic hopping energy is seen which is not simply linear. The low temperature resistivity is seen to be fit better by a model of single magnon scattering, and a near linear correlation between the resistivity due to magnon scattering and static impurities is observed.