Resistivity and 1/f noise in nonmetallic phase-separated manganites - art.no. 174424

A simple model is proposed to calculate the resistivity, magnetoresistance, and noise spectrum in nonmetallic phase-separated manganites containing sm all metallic droplets (magnetic polarons). The system is taken to be far fr om the percolation transition into a metallic state. It is assumed that the charge transfer occurs due to electron tunneling from one droplet to anoth er through the insulating medium. As a result of this tunneling, the drople ts acquire or lose extra electrons forming metastable two-electron and empt y states. In the framework of this model, explicit expressions for de condu ctivity and noise power of the system are derived. It is shown that the noi se spectrum has 1/f form in the low-frequency range.