Defects in solids

Intrinsic point defects:

Point defects are not easy to directly detect. Several techniques have been used to study them. Two physicists, Frenkel and Schottky used conductivity and density data to identify specific types of point defects.

Schottky defect – Vacancy in an otherwise perfect lattice. Point defect where atom / ion is missing from its usual point in the lattice. Overall stoichiometry usually unaffected as there is normally equal numbers of vacancies at both M and X sites preserving charge balance.

These defects are encountered more commonly when metal ions are able to easily assume multiple oxidation states.

Schottky defect shown opposite (fig. 15)