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Materials Science at Oregon State University

TEM: The Materials Science Sandbox

Date: Thursday, Feb 28th
Presenter: Dr. Pete Eschbach, Director, OSU Microscopy Facility

Abstract


The modern Transmission Electron Microscope is more than just about producing images. It is a Materials Science Sandbox. Allowing investigators to determine structure, chemical composition, and precise determination of phase. You could say that the TEM has capabilities borrowed from other techniques: line profiles and bonding information like XPS (X-ray photo electron spectroscopy), Diffraction analysis like XRD(X-Ray diffraction), and of course doing all of these things at super high spatial resolution and creating wonderful images. Downfalls do exist such as poor sample statistics and the need for careful sample preparation and these will be discussed. The OSU TEM has both a good electron energy loss (EELS) capability and world class x-ray analysis (EDS) capability. Examples will be given where both were detected simultaneous. Is TEM really the poor cousin of XRD? Just from a diffraction resolution point of view and this limit – Ewald sphere- is but it has other advantages. It provides complimentary structural determinations adjacent to X-ray diffraction as electron diffraction does not suffer from Friedel’s law as most X-ray patterns are kinematic while electron diffraction this is not necessarily the case. Examples will be discussed where determining right vs left handiness of a medicines solved a disastrous mystery. Finally, HRTEM images of lattice planes will be discussed and demonstrated with the use of a coupled double pendulum.