On the optimization of the large magnetoresistance of Ag2Se

We describe an attempt to find the key parameter for the optimization of recently discovered large magnetoresistance in non-stoichiometric silver chalcogenides. Our measurements of the resistivity, magnetoresistance and the Hall effect of Ag2Se and their simple analysis lead us to the conclusion that the most important optimization variable is the Hall mobility of the charge carriers. We suggest that the largest magnetoresistance may be expected in the samples with the Hall mobility equal to about 0.1 m(2)/Vs.