EXAFS study of Zr environment in amorphous precursors of Pb(Zr,Ti)O-3

Homogeneity of the amorphous sol-gel precursors of Pb(Zr,Ti)O-3 ferroelectr ic ceramics is studied at various Zr/Ti ratios. From Zr K-edge EXAFS spectr a the immediate vicinity of Zr atoms is determined. A distorted octahedron of O atoms with all the bonds continued in Zr-O-Zr links is observed down t o Zr/Ti ratio of 1:1, indicating the prevalent homocondensation of Zr. In t he precursor with Zr/Ti ratio of 25/75 a smaller distortion of O octahedra is observed and heterometallic bonding Zr-O-Ti is found. Mixing of the two metals (Zr, Ti) at molecular level is thus established at low Zr/Ti ratios.