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 5500.3em0exK 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^α-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 α coefficient and the polaron formation energies Eg as a function of the metal-insulator transition temperature TMI has been found. Our results indicate the possibility of describing the transport properties in CMR manganites in terms of a single disorder parameter.