Quantitative analysis of atomic disorders in full-Heusler Co2FeSi alloy thin films using x-ray diffraction with Co Kα and Cu Kα sources

The authors developed a new analysis technique for atomic disorder structures in full-Heusler alloys using x-ray diffraction (XRD) with Co K alpha and Cu K alpha sources. The technique can quantitatively evaluate all the atomic disorders for the exchanges between X, Y, and Z atoms in full-Heusler X(2)YZ alloys. In particular, the technique can treat the DO3 disorder that cannot be analyzed by ordinary Cu K alpha XRD. By applying this technique to full-Heusler Co2FeSi alloy thin films formed by rapid thermal annealing (RTA), RTA-temperature (T-A) dependence of the atomic disorders was revealed. The site occupancies of Co, Fe, and Si atoms on their original sites were 98%, 90%, and 93%, respectively, for the film formed at T-A=800 degrees C, indicating that the RTA-formed Co2FeSi film had the L2(1) structure with the extremely high degree of ordering. (c) 2010 American Institute of Physics. [doi: 10.1063/1.3350914]