For your report on TEM and Optical Diffraction:

1. Read the general instructions on reports given the first day of classes.

2. Your introduction should have the principles of the TEM and of Optical diffraction.

2. For the Optical Diffraction only:

a. We want a structure of the grid that gave a hexagonal pattern (with a sketch) In problem 4, Assignment 1 of ENMA 460, you were given a hexagonal direct unit cell and asked to calculate the inverse vectors. You were asked to show that it was a hexagonal. Apply this to this problem.

b. An estimate, based on the 10 µm separation pattern, of the separation of the pattern that gave the hexagonal grating. To do this, use the equation given in the text,

2s ~ 2/d

to get a relation between the distance measure in cm for the 10 mm grating an use this relation to determine what separation exists in the hexagonal grating:

2s₁ ~2/10 mm

2s₂ ~ 2/x mm

c. An estimate of the error in your measurement.

3. For the TEM and Optical Diffraction measurements:

a. We want a list of separations obtained from the TEM diffraction study. We want an estimate of the amount of error. To do the TEM diffraction, use:

2Ll/2r,

where 2L = the camera length which is 2 m for the cross section and 2.5 m for the plan view (see picture, bottom right), l = 0.0197Å, is the wavelength of the electron beam and 2r = the distance that you measure from point to point. Use only the equation above for the pictures taken with the TEM.

b. We want a list of the separations obtained from the Optical diffraction analysis of the pictures, an estimate of the error in the measurement and a comment of how the diffraction pattern was obtained compared with the TEM diffraction pattern (how large was the area). Does this contribute to the error. To do the optical analysis, use the measurement obtained fro LAO (the substrate) in the experiment (this distance is equivalent to 3.79Å). Use the same equations you used for the hexagonal fiber to do the calculation. Please note, the cross sectional view was taken with a magnification of 500K (not 300K, as I originally said) and the plan view was taken with 400K (see bottom right of negative). So the measurement must be adjusted by 4/5 (sorry).

c. We want a measurement of the FFT obtained by using the program. Based yourself on the measurement of the substrate, 3.79Å. Use the relation

2s ~ 2/d

and the steps described for the hexagonal fiber to find the dimensions.

d. Include at least one picture from the TEM (you can use the ones scanned for the FFT) one picture from the Optical diffraction, and one from the FFT in your report (include all pictures in your notebook).

4. This report includes two experiments so you can exceed the 6-page limit, but not exceed 12.