#################################################### # Yen-Ru Lee # requesting 6 days, at minimum=5 days # beamline 33ID, Growth studies of Fe3O4/MgO films using pulsed laser deposition # instrument 33ID-D laser #################################################### # top:/home/www/beamtime-requests/req00844.txt # UNICAT Member Beam Time Request #844 # created Sun Aug 21 14:19:03 CDT 2005 #################################################### apsrun: 2005-03 beamline: 33ID collaboration: Yes 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. 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. At Run 2005-2, we found the Fe3O4 can form high-tower islands film.We had already succeed in growing high-tower island and flat surface film on substrate MgO. We got the reflectivity data with 5,6,7, 30 and 50 ML at 325C and 20, 50 ML at 350C. The others are about 400C to 450C. Upon this data, 7ML is the critical thickness, 20 and 30 ML are the film with high-tower islands and 50ML is flat. I think we still need to have some more reflectivity and insitu PLD data at 10, 20, 40 and 60ML to understand the high-tower islands growth. I think the distribution of island size, height and coverage at different thickness may follow some bimodal growth, after certain thickness the islands size distribution would become uniform. Understanding the dependence of the island size and uniformity on different thickness might be important. equipment_required: experiment: Growth studies of Fe3O4/MgO films using pulsed laser deposition foreign_nationals: hazards: N/A instrument: 33ID-D laser instrument_other: minimumdays: 5 name: Yen-Ru Lee nonmembers: submit: Submit unacceptable_dates: N/A z34ID_change_undulator: no z34ID_details: z34ID_parasitic: no #REMOTE_HOST: junolee-m.mrl.uiuc.edu #REMOTE_ADDR: 130.126.101.66 #CONTENT_LENGTH: 2073 #HTTP_REFERER: http://www.uni.aps.anl.gov/admin/unireq.html #HTTP_USER_AGENT: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.8) Gecko/20050511 Firefox/1.0.4