A simple model is proposed to calculate resistivity, magnetoresistance, and
noise spectrum in non-metallic phase-separated manganites containing small
metallic droplets (magnetic polarons). The system is taken to be far from the
percolation transition into a metallic state. It is assumed that the charge
transfer occurs due to electron tunneling from one droplet to another through
the insulating medium. As a result of this tunneling, the droplets acquire or
lose extra electrons forming metastable two-electron and empty states. In the
framework of this model, explicit expressions for dc conductivity and noise
power of the system are derived. It is shown that the noise spectrum has 1/f
form in the low-frequency range.Comment: 6 pages, 1 fugure include