Homogeneous-inhomogeneous models of Agx(Ge0.25Se0.75)100−x bulk glasses

Mössbauer spectrometry on samples (0⩽x⩽25) containing 0.5 at% of 57Fe is performed at T⩽300 K. The main contribution to the glasses spectra correspond to low spin Fe2+ in octahedral coordination and high spin Fe2+ in distorted octahedral environments. The relative population of both sites changes continuously as Ag concentration varies denoting that the change in the transport behavior obeys to a percolation phenomenon. The low temperature results are discussed with the aim to throw light on the controversy about the homogeneity-inhomogeneity of the studied bulk glasses.