Disorder-Order Transformation of NiMn Thin Films

The atomic disorder-Order transformation of NiMn thin films in the multilayers Si/Ta/NiMn/Al and Si/Ta/NiFe/NiMn/Al undergoing different number of annealing cycles at 300C for 5 hours was studied. Quantitative calculations of X-ray diffraction patterns show that annealing at a high temperature for several cycles can greatly facilitate the atomic ordering process of NiMn thin films. The relative amount of the ordered fct phase in NiMn thin films increases continuously with the increased number of annealing cycles. But for the multilayers containing a NiFe layer, the atomic ordering process of NiMn thin films is much slower compared with those without a NiFe layer. It is then evident that NiFe impedes the atomic ordering process of NiMn thin films.