Hostname: page-component-78c5997874-4rdpn Total loading time: 0 Render date: 2024-11-19T08:35:45.641Z Has data issue: false hasContentIssue false

Goniometry of Direct Lattice Vectors Supporting Students' Comprehension of Crystallographic Core Concepts and Demonstrating Image-Based Nanocrystallography

Published online by Cambridge University Press:  15 March 2011

P. Moeck
Affiliation:
Department of Physics, Portland State University, P.O. Box 751, Portland, OR 97207-0751, [email protected]
K. Padmanabhan
Affiliation:
Department of Physics, Portland State University, P.O. Box 751, Portland, OR 97207-0751
W. Qin
Affiliation:
Motorola Technology Solutions/SPS, MD CH305, Chandler, AZ 85284
P. Fraundorf
Affiliation:
Department of Physics and Astronomy and Center for Molecular Electronics, University of Missouri at St. Louis, MO 53121
Get access

Abstract

We are of the opinion that students of an introductory materials science and engineering course should gain a thorough understanding of crystallographic core concepts by applying them quasi-experimentally in computer simulation sessions that run parallel to the lectures. Software simulations of goniometry of direct lattice vectors in a transmission electron microscope (TEM) will serve two purposes at once: to introduce students to practical aspects of electron microscopy and support their comprehension of crystallographic core concepts. We use the programming software Matlab and Java (Jmol applets) on a PC platform for the creation of software simulations that demonstrate this methodology and complement already existing software simulations. The newly created software is used in classroom demonstrations of an introductory materials science and engineering course at Portland State University and will become freely accessible over the internet. This software will also support and promote image-based nanocrystallography in TEM.

Type
Research Article
Copyright
Copyright © Materials Research Society 2004

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

[1] Wuensch, B., Journal of Chemical Education 65, 494 (1988).Google Scholar
[2] Allen, S.M. and Thomas, E.L., The Structure of Materials (John Wiley & Sons, 1999).Google Scholar
[3] Barrett, C.S., Structure of Metals, Crystallographic Methods, Principles, and Data (McGraw- Hill, 1943).Google Scholar
[4] http://www.umsl.edu/∼fraundor/nanowrld/dtemspec.htmlGoogle Scholar
[5] Fraundorf, P.B. and Pongkrapan, N., Proc. 2004 Microscopy and Microanalysis Meeting of the Microscopy Society of America, Savannah (Georgia), August 1-5, 2004.Google Scholar
[6] http://www.thorlabs.com and http://www.thorlabs.com/Thorcat/6700/6794-E0W.pdfGoogle Scholar
[7] Callister, W.D. Jr., Mat. Res. Soc. Symp. 760E, JJ6.1.1 (2003) and W.D. Callister Jr., Fundamentals of Materials Science and Engineering: An Integrated Approach (John Wiley & Sons, 2005).Google Scholar
[8] Cahn, R.W., MRS Bulletin, July 2003, 468.Google Scholar
[9] Cahn, R.W., The Coming of Materials Science (Pergamon 2001).Google Scholar
[10] Schaffer, J.P., Saxena, A., Antolovich, S.D., Sanders, T.H., and Warner, S., The Science and Design of Engineering Materials (McGraw-Hill, 1999).Google Scholar
[11] Fraundorf, P., Ultramicroscopy 22, 225 (1987).Google Scholar
[12] Qin, W. and Fraundorf, P.B., Ultramicroscopy 94, 245 (2003).Google Scholar
[13] Möck, P., German patents DE 4037346 A1 and DD 301839 A7, priority date: 21 November, 1989.Google Scholar
[14] Since the intersection of the goniometer axes (tilt-rotation center) does not coincide with the center of the Si model crystal in the thinnest region of the disk in Figs. 3a,b, there are projection effects that need to be taken into account in measurements of the spacings of crystallographic planes. Alternatively, one may try to adjust the tilt-rotation center to the correct specimen “height” and “lateral position of interest” – just as one would do in a real TEM. Nevertheless, the crystallography of Si is reasonably well revealed by this matching pair of two-dimensional projections. The length markers in Figs. 1c, 2a, and 2b are adjusted to the size of the buckyball, which was at the tilt-rotation center when these images were captured. Note also that the point-to-point resolution of the simulated TEM is superb as the so called “Si dumbbells”, i.e. the {400} lattice spacings which are in reality only 0.136 nm wide, are clearly revealed in Fig. 3a.Google Scholar
[15] Johari, O. and Thomas, G., The stereographic projection and its application (Wiley, 1969).Google Scholar
[16] Hake, R.R., Am. J. Phys. 66, 64 (1998); http://www.physics.indiana.edu/∼sdi/ajpv3i.pdfGoogle Scholar
[17] http://cst-www.nrl.navy.mil/lattice/Google Scholar
[18] http://jmol.sourceforge.net/Google Scholar
[19] www.physics.pdx.edu/∼pmoeck/goniometry.htmGoogle Scholar