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# Aaron Gray <ajgray@uiuc.edu>
# requesting 5 days, at minimum=4 days
# beamline 33ID, Pb films on vicinal Si surfaces near the melting temperature
# instrument 33ID-E surface
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# top:/home/www/beamtime-requests/req01085.txt
# UNICAT Member Beam Time Request  #1085
# created Wed Dec 13 15:47:52 CST 2006
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apsrun:
	2007-01

beamline:
	33ID

collaboration:
	Yes

contact:
	ajgray@uiuc.edu

days:
	5

description:
	Solid thin films have been studied widely and continue to be of interest, however their liquid counterparts have not received as much attention. In past experiments we found it dificult to see the scattering contribution from liquid Pb films over the contribution from the Si substrates we used.   In recent experiments by using Si substrates wuth large miscuts it was found that the scattering contribution from liquid Pb films could be seen.  In this experiment Pb films, over 75 monolayers thick, will be grown on Si (111) substrates with a miscut greater than 4 degrees.  These films will be heated above the Pb melting temperature, while the x-ray reflectivity is being observed.   So that the solid liquid transition can be studied, although in the bulk case the transition is first order it may be continuous for a film. After the melting transition is reached scattering at small angles from the liquid will be observed.  Previous studies, examining the reflectivity at small angles, from bulk liquid metals show surface induced layering, capillary wave effects.  This study may be able to shed light on the effect of decreasing the thickness of the liquid, and what role quantum size effects may play in the liquid structure as well as the solid liquid transition.

equipment_required:
	CCD camera

experiment:
	Pb films on vicinal Si surfaces near the melting temperature

foreign_nationals:
	

hazards:
	Liquid Nitrogen will be used to cool the sample.

instrument:
	33ID-E surface

instrument_other:
	

minimumdays:
	4

name:
	Aaron Gray

nonmembers:
	Hawoong Hong, Tai Chiang

submit:
	Submit

unacceptable_dates:
	

z34ID_details:
	


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