  It is shown that charge transport in substituted manganites
(La1/3Sm2/3)0.67Ba0.33-xSrxMnO3 (x = 0.0, 0.1, 0.2 and 0.33) is through
polarons which are formed through electron-phonon coupling whose strength
determines the mobility of the charge carrier. For weak coupling the free
phonon mode is only slightly affected but in strong coupling the free phonon
mode disappears and "displaced" phonon modes appear. This is seen directly in
IR-spectra.
