Influence of a single disorder parameter on the conduction mechanisms in manganite thin films

We have systematically studied the transport properties of colossal magnetoresistance (CMR) manganite films at temperatures of up to 550 K by changing parameters influencing the amount of disorder in the system. Independent of the type and amount of disorder, the resistivity can always be described using a T-alpha-power law in the ferromagnetic-metallic phase and a thermally activated behavior in the polaronic-insulating phase. A linear correlation between both the value of the alpha coefficient and the polaron formation energies E-g as a function of the metal-insulator transition temperature T-MI has been found. Our results indicate the possibility of describing the transport properties in CMR manganites in terms of a single disorder parameter.