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# Yen-Ru Lee <junolee@uiuc.edu>
# requesting 6 days, at minimum=6 days
# beamline 33ID, Growth studies of Fe3O4/MgO films using pulsed laser deposition
# instrument 33ID-D laser
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# top:/home/www/beamtime-requests/req00780.txt
# UNICAT Member Beam Time Request  #780
# created Sun Apr 17 16:09:40 CDT 2005
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apsrun:
	2005-02

beamline:
	33ID

collaboration:
	No

contact:
	junolee@uiuc.edu

days:
	6

description:
	The magnetite Fe3O4 is the earliest known magnet, and is still an interesting and important material owing to its catalytic, magnetic, and semiconducting properties as well as widespread applications. The chemical and physical structures of Fe3O4 films, including stoichiometry and grain size and shape, can significantly influence the magnetic and electrical properties. For instance, variations in stoichiometry in Fe3O4 can reduce the magnetization through iron vacancies in the B-site magnetic sublattice. The grain size and shape distribution in a film are strongly dependent on the film thickness. With decreasing film thicknesses, the grain size generally decreases, leading to a corresponding reduction in the Verwey transition temperature Tv. At sufficiently small film thicknesses, this transition can be completely suppressed. However, other growth conditions, including substrate temperature and growth rate, can also substantially affect the film microstructure. The proposed experiment is to investigate the structure of thin Fe3O4 films prepared by pulsed laser deposition (PLD) on MgO, sapphire and MgAl2O4 substrates. MgO is commonly used as a substrate for the deposition of Fe3O4 due to a good lattice match, thus allowing pseudomorphic growth. However, antiphase domains can form, which can affect the film magnrto-transport properties. These structural issues as well as the dynamics of film deposition by PLD will be investigated with surface diffraction. 
At previous Run 2005-1, we had already success in depositing Fe3O4 on MgO substrate with two-dimensional full-mono-layer growth after enough Fe3O4 film thickness. However, the substrate temperature during deposition is a key issue for the film quality and stoichiometry. We had found that for different deposition temperature the film growth mode regarding layer-by-layer at first beginning without enough magic thickness. We still need to study more clearly at different deposition temperature and film thickness.

equipment_required:
	Laser ablation chamber

experiment:
	Growth studies of Fe3O4/MgO films using pulsed laser deposition

foreign_nationals:
	

hazards:
	N/A

instrument:
	33ID-D laser

instrument_other:
	

minimumdays:
	6

name:
	Yen-Ru Lee

nonmembers:
	

unacceptable_dates:
	

z34ID_details:
	


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