Temperature- and field-dependent far-infrared studies of (La$_{0.4}$Pr$_{0.6}$)$_{0.67}$Ca$_{0.33}$MnO$_{3}$ films

We report far-infrared temperature (300 K-20 K) and magnetic field (0-18 T) dependent reflectance and transmittance studies of 1000 A-thick hole-doped LPCMO thin films. Temperature-dependent measurements show evidence of phase coexistence in the sense that the film still shows insulating behavior at very low temperatures. Magnetic field studies at 4.2 K observe an insulator to metal transition, seen as large changes in reflectance and transmittance. The spectra are analyzed by using standard multilayer film-fitting procedures to extract the optical conductivity and other optical constants. The results are discussed in the context of effective medium approximations.