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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 2:33 |
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Conference: Bucharest University Faculty of Physics 2010 Meeting
Section: Solid State Physics and Materials Science
Title:
Molecular beam epitaxy deposition of Fe on Si(001)
Authors:
A. Segal (1), C. Teodorescu (2), Daniela Dragoman (1)
Affiliation:
(1)Univ. Bucharest, Physics Dept.
(2) National Institute of Materials Physics, Bucharest, Romania
E-mail
danieladragoman@yahoo.com
Keywords:
molecular beam epitaxy, ultrathin films
Abstract:
We present a study of the deposition process of ultrathin ferromagnetic Fe layers on Si(001) using the molecular beam epitaxy method in ultrahigh vacuum. The study is undertaken as a function of the amount of Fe deposited and the substrate temperature. All stages of the process are detailed, starting from the preparation of Si(001). In particular, the physical phenomena associated with cleaning of Si(001) through a sequence of annealing processes are discussed. These phenomena are identified by monitoring the crystal surface with tools used for both structural characterization, such as low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED), and the interface reactivity is characterized by Auger electron spectroscopy. A systematic study of Si(001) cleaning allows an unambiguous assignment of oxidized and unoxidized silicon. After Si(001) preparation, the deposition process of Fe and its control methods are presented. Afterwards, the samples are capped with Au and ex situ characterized by magneto-optical Kerr effect (MOKE) which reveals the magnetic properties of the system Fe/Si(001) in both room temperature and high temperature depositions. A general trend established is that a higher temperature stabilizes a better surface ordering, but enhances the Fe and Si interdiffusion and therefore decreases the magnetism. Also, a surprising effect obtained by Fe deposition at room temperature is that, despite the rapidly vanishing of long range order with Fe deposition, there exists a significant uniaxial in-plane magnetic anisotropy. When the deposition is performed at high temperature there is still observed a weak ferromagnetism with saturation magnetization of about 10% from its value obtained for room temperature deposition.
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