Raju, John K; Dr.Kuriakose, V C(Cochin University of Science and Technology, January 6, 1999)
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Abstract:
The thesis deals with the study of super conducting properties of layered cuprates
within the frame work of a modified Lawrence-Doniach (LD) model. The thesis is
organized in seven chapters. Chapter I is a survey of the phenomena and theories
of conventional superconductivity which can serve as a springboard for launching
the study of the new class of oxide superconductors and it also includes a
chronological description of the efforts made to overcome the temperature barrier.
Chapter II deals with the structure and properties of the copper oxide superconductors
and also the experimental constraints on the theories of high te:::nperature
superconductivity. A modified Lawrence-Doniach type of phenomenological model
which forms the basis of the presnt study is also discussed. In chapter III~ the temperature
dependence of the upper critical field both parallel and perpendicular to
the layers is determined and the results are compared with d.c. magnetization
measurements on different superconducting compoilllds. The temperature and
angular dependence of the lower critical field both parallel and perpendicular to
the layers is also discussed. Chapters IV, V and VI deal with thermal fluctuation
effects on superconducting properties. Fluctuation specific heat is studied in chapter
IV. Paraconductivity both parallel and perpendicular to the layers is discussed
in chapter V. Fluctuation diamagnetism is dealt with in chapter VI. Dimensional
cross over in the fluctuation regime of all these quantities is also discussed. Chapter
VII gives a summary of the results and the conclusions arrived at.
Description:
Department of Physics, Cochin University of Science and Technology