Scanning Microscopy


The purpose of this paper is to survey the methods that are available for probing surfaces and grain boundaries of high temperature superconductors. Various surface-sensitive spectroscopies are applied to the analysis of YBa2Cu3O7-x and Bi2Sr2CaCu2O8+x including photoelectron spectroscopy, spatially-resolved electron energy loss spectroscopy, and scanning electron microscopy (SEM). One of the major sources of contamination at surfaces and grain boundaries is found to be BaCO3. The cleavage surface of single crystal Bi2Sr2CaCu2O8+x is inert and can be used to probe bulk properties of superconductors, even with surface-sensitive techniques. The orbital character of the superconducting oxygen 2p holes is found to be Px,y, with x,y in the a,b plane. Photoemission at the Fermi level indicates a Fermi liquid nature of these states.

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