Transmission electron microscopy study of the microstructure of amorphous Co-P alloy films on various spatial scales

Abstract

Amorphous Co-P alloy films containing 18–20 at % P are shown to have a network-type microstructure with structural heterogeneity sizes of 30–100 A on nanometer and atomic spatial scales. The degree of short-range ordering is different in these heterogeneities: high-density regions mainly consist of disordered atoms; in some places, there are 10- to 20-A clusters with signs of atomic ordering; and there are regions with a low material density characterized by the absence of atomic ordering. The use of aberration corrected microscopy allowed us to establish that the network microstructure is complex: the regions of high and low densities observed on the nanometer spatial scale as homogeneous media have, on the atomic scale, a structural heterogeneity that manifests itself as further separation into regions with different material densities and different degrees of short-range atomic ordering. Surface defects as pores and holes in the amorphous films are shown to be activating factors of the onset of crystallization.