On the optimization of the large magnetoresistance of Ag2Se

We describe an attempt to find the key parameter for the optimization of re cently discovered large magnetoresistance in non-stoichiometric silver chal cogenides. Our measurements of the resistivity, magnetoresistance and the H all effect of Ag2Se and their simple analysis lead us to the conclusion tha t the most important optimization variable is the Hall mobility of the char ge 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.