The Dominant Type of Atomic Disorder in α-Al2O3

Comparison of the energy of formation per defect, as deduced from experimental results on α‐Al2O3 doped with donors and acceptors on the basis of various models, with theoretical values calculated by Dienes et al. for various disorder models shows closest correspondence of the exFrimentd values with the smallest theoretical values (obtained for Schottky disorder). This indicates that the theoretical results are reliable and that Schottky disorder is the major type of atomic disorder in α‐Al2O3. Creep data on Al2O3:Fe by Hollenberg and Gordon make it possible to determine the enthalpy of Frenkel disorder of Al.