The magnetoresistance of homogeneous and heterogeneous silver-rich silver selenide

The magnetoresistance (MR) effect of the low-temperature phase of silver selenide (α-Ag2+δSe) is measured as a function of composition. Very small composition variations in the order of Δδ=10−6 are achieved by coulometric titration and can be performed simultaneously during the MR measurement. A homogeneous Ag2+δSe shows an ordinary magnetoresistance (OMR) effect, which can be well described by the two-band model. For silver selenide with a heterogenous silver excess, we found quite a different MR behavior. Up to a minor silver excess of 1×10−4 10−2) shows again an OMR effect.