Ternary systems defect structures

In this chapter, we will discuss the generation modes of thermodynamically stable point defects and the defect-chemical logic to calculate the equilibrium defect structure of a given system. As a stereotype of systems, we will consider only a binary oxide MO, but the idea and logic can be readily extended to other binary, ternary and higher systems with minor modifications [2-6]. 

However, in some cases when the structure of the initial samples is already defective (fine-grained structure or a large number of radiation defects), the possibility for a two-phase zone to form in a ternary system increases. If, in addition, the diffusion parameters of the initial alloys imply no other diffiision modes (for example, interphase boundary movement with the concentration jump on it (along tie-line) or growth of intermediate phases), then the system has to relax to equilibrium through the inevitable formation of a two-phase zone. 

In what follows below, we first provide a description of our theoretical model. We then show how one can control the evolution of such systems by varying the reaction rate coefficients in a specified manner. In subsequent sections, we discuss the formation of defect-free structures in the binary and ternary systems via a combination of stationary and moving light sources. We then go on to describe the use of a photomask to control the structure formation within thin films of the ABC blends. 

Structural Imperfections. In many respects HREM has had a greater impact upon our knowledge of the nature of the atomic reorganization at crystalline imperfections than any other single technique. One of the very first contributions of HREM as a new analytical and structural tool was described in the paper by Iijimia (42) in 1971 on 2 10 29 v -ewe< down to its b - axis. Structural faults, arising from subtle fluctuations in composition, could be clearly seen in the block-structure (based on NbO octahedra) which is a feature of this ternary oxide system. More than a decade later similar materials are yielding to active scrutiny by HREM, and Horiuchi (43), for example, has shown how point defects may be directly viewed... 

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