  The authors developed a new analysis approach for evaluation of atomic
ordering in full-Heusler alloys, which is extension of the commonly used
Webster model. Our model can give accurate physical formalism for the degree of
atomic ordering in the L21 structure, including correction with respect to the
fully disordered A2 structure, i.e., the model can directly evaluate the degree
of L21-ordering under a lower ordering structure than the complete B2-ordering
structure. The proposed model was applied to full-Heusler Co2FeSi alloy thin
films formed by rapid thermal annealing. The film formed at TA = 800 C showed a
relatively high degree of L21-ordering of 83 % under a high degree of
B2-ordering of 97 %.
