Development of a technique for a quantitative study of the order and composition of an iron-palladium alloy on the nanometre scale in an electron microscope with imaging filter

In an ordered alloy the degree of order depends on the chemical composition and the microstructure of the alloy. Here we describe a technique to obtain, from an angular-resolved energy-loss spectrum taken in a transmission electron microscope with an imaging filter, quantitative information on the degree of short-range order and the local composition, with a spatial resolution of some nanometres. As a test, the procedure is applied in plan-view geometry to an iron-palladium alloy layer grown on a magnesium oxide substrate. The method is also applicable to the investigation of local changes of order and composition in crosssectional geometry where the spatial resolution obtainable is primarily limited by the electron probe size.