Mössbauer investigation of rare earth sites in europium containing glasses

Samples of crystalline and amorphous trivalent europium metaphosphate were examined by (151)EU Mossbauer spectroscopy. The disorder of the lanthanide sites in the glass has been investigated by comparing the glass to the corresponding crystalline material. In the crystalline and amorphous samples, the rare earth is accommodated in a site on average distorted with respect to cubic symmetry; this site has no threefold or fourfold symmetry axis. In the glass, the structural disorder has been evaluated by broadening the Lorentzian component of the quadrupole multiplet with respect to the crystal. The spectrum of the amorphous sample was also analysed using a convolution method, which reproduces the distribution of the quadrupole interaction parameter due to the structural disorder