CALCULATION OF THE LONG-RANGE ORDER-PARAMETER FROM ATOM-PROBE DATA

In addition to the known diffraction techniques, field-ion microscopy with atom probe is well established for determining the long-range ord er parameter. The site occupation probabilities of the chemical specie s on the different sublattices may be estimated from experimental prof iles. However, this evaluation method demands that the superstructure planes be identified unequivocally from the data. This condition is no t fulfilled in all cases. We propose a new analytical method for which this condition need not be met. (C) 1997 Elsevier Science Ltd.