Magnetoresistance in Ag2+δSe with high silver excess -: art. no. 072102

In the present study, we investigated the galvanomagnetic transport properties of polycrystalline AgxSe thin films with silver excess in the range from x = 1.5 to 18. The results prove that the silver excess controls the transition from linear magnetoresistance (MR) behavior to the quadratic ordinary MR and the temperature for the metal-semiconductor transition. Analyzing the MR effect by Kohler's rule and comparing the results with the field-free resistivity we observe for 2 < x < 2.3 a steep rise of the product of mean free path and electron concentration (lambda - .n(2/3)). We interpret this result as a consequence of the percolation of nanoscale silver networks within the semiconducting matrix, i.e., as a consequence of the two-phase character of the system. (C) 2005 American Institute of Physics.