Bls Studies of Exchange Coupling in The Iron Whisker/Cr/Fe System

1995 ◽  
Vol 384 ◽  
Author(s):  
J.F. Cochran ◽  
K. Totland ◽  
B. Heinrich ◽  
D. Venus ◽  
S. Govorkov
Keyword(s):  
Thin Film ◽  
Coupling Strength ◽  
Kerr Effect ◽  
Exchange Coupling ◽  
Molecular Beam ◽  
Growth Conditions ◽  
Antiferromagnetic Coupling ◽  
Ferromagnetic Coupling ◽  
Film Magnetization

ABSTRACTBrillouin light scattering (BLS) and magneto-optic Kerr effect have been carried out on a series of specimens consisting of a Fe(001) whisker substrate upon which thin Cr(001) and Fe(001) layers have been deposited by means of molecular beam epitaxy in ultrahigh vacuum. The Fe film was 20 monolayers (ML) thick, and the Cr(001) films were grown having various thicknesses. It is demonstrated that BLS thin film frequencies measured in the saturated magnetic state with the thin film magnetization parallel with the applied magnetic field can be used to obtain the exchange coupling strength between the thin film and whisker magnetizations both for antiferromagnetic coupling and for ferromagnetic coupling, provided that the ferromagnetic coupling is not too strong. It is also shown that the coupling strength is extremely sensitive to the quality of the chromium growth: a small deterioration in the growth conditions has been found to reduce the exchange coupling by nearly a factor of two.

SHORT-PERIOD OSCILLATIONS OF THE MAGNETIC COUPLING OF EPITAXIAL GROWN Fe/Mo/Fe SANDWICHES ON Mo(100)

1992 ◽  
Vol 06 (14) ◽  
pp. 839-849 ◽  
Author(s):  
Z. Q. QIU ◽  
J. PEARSON ◽  
S. D. BADER
Keyword(s):  
Simple Model ◽  
Electron Diffraction ◽  
Hysteresis Loop ◽  
Kerr Effect ◽  
Exchange Coupling ◽  
Magnetic Coupling ◽  
Oscillatory Behavior ◽  
Ferromagnetic Coupling ◽  
Short Period

Epitaxial Fe / Mo / Fe sandwiches grown onto a Mo (100) single crystal were characterized in situ by electron diffraction and the magneto-optic Kerr effect. The intervening Mo layer is wedge shaped to facilitate the study of the magnetic coupling between the two (14-monolayer thick) Fe films as a function of Mo thickness. The exchange coupling between the Fe films across Mo was found to exhibit oscillatory behavior between antiferromagnetic (AF) and ferromagnetic coupling with a periodicity of ~3 ML of Mo . The shape of the hysteresis loop of the AF-coupled samples was calculated from a simple model that reproduces most of the experimental features.

Raman Scattering and Photoluminescence of Mg Doped GaN Films Grown by Molecular Beam Epitaxy

1997 ◽  
Vol 468 ◽  
Author(s):  
G. Popovici ◽  
G. Y. Xu ◽  
A. Botchkarev ◽  
W. Kim ◽  
H. Tang ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Tensile Stress ◽  
Molecular Beam ◽  
Growth Conditions ◽  
Longitudinal Optical ◽  
Raman Shift ◽  
Longitudinal Optical Phonon ◽  
Photoluminescence Peak ◽  
Mg Doped

ABSTRACTRaman, photoluminescence, and Hall measurements are reported for Mg doped GaN films grown by molecular beam epitaxy. The compressive and tensile stress determined by the Raman shift of the phonon lines is due to the growth conditions rather than the presence of Mg in the film. The photoluminescence peak of near band-to-band transitions is also shifted to larger (smaller) energies by the compressive (tensile) stress. The study of the longitudinal optical phonon of the Ai branch shows that its Raman line shape is affected not only by phonon-plasmon interactions but by the crystalline quality of the film, as well.

scholarly journals Изопараметрические гетероструктуры AlInGaAsP/InP и их свойства

2019 ◽  
Vol 53 (7) ◽  
pp. 903
Author(s):  
Д.Л. Алфимова ◽  
Л.С. Лунин ◽  
М.Л. Лунина ◽  
А.С. Пащенко ◽  
Э.М. Данилина
Keyword(s):  
Thin Film ◽  
Liquid Phase ◽  
Indium Phosphide ◽  
Surface Quality ◽  
Growth Conditions ◽  
Epitaxial Films ◽  
Structural Perfection

The paper discusses the influence of growth conditions on the structural perfection of AlInGaAsP/InP thin-film heterostructures. The main parameters determining the structural perfection and surface quality of thin AlInGaAsP epitaxial films grown on indium phosphide substrates from the liquid phase in the temperature gradiend field are determined.

Studies of Exchange Coupling in Fe (001) Whisker/Cr/Fe Structures using BLS and Rheed Techniques.

1993 ◽  
Vol 313 ◽  
Author(s):  
B. Heinrich ◽  
M. From ◽  
J.F. Cochran ◽  
L. X. Liao ◽  
Z. Celiński ◽  
...  
Keyword(s):  
Coupling Strength ◽  
Exchange Coupling ◽  
High Energy ◽  
Variable Number ◽  
Antiferromagnetic Coupling ◽  
Iron Film ◽  
First Principles Calculations ◽  
Iron Whisker ◽  
Short Period ◽  
Coupling Strengths

ABSTRACTThe conditions for an almost perfect growth of smooth Cr (001) films on an iron whisker substrate have been investigated by means of reflection high energy electron diffraction (RHEED). The exchange interaction between 20 Monolayer thick Fe (001) films separated from a bulk whisker Fe (001) substrate by a variable number of Cr (001) Monolayers (ML) has been investigated by means of Brillouin light scattering experiments (BLS). These experiments show unambiguously that the exchange coupling strength between the iron film and the iron whisker can be described by a short wavelength oscillatory term superposed on a slowly varying antiferromagnetic background. The BLS data enabled one to separate the bilinear and the biquadratic contributions to the antiferromagnetic exchange coupling terms. Both the bilinear and the biquadratic coupling strengths exhibited a short period oscillatory dependence on the Cr interlayer thickness (∼2 Monolayers). Maxima in the bilinear antiferromagnetic coupling strength occur for an odd number of Cr Monolayers. This observation is not in agreement with first principles calculations. The first phase inversion has been found to occur between 4 and 5 ML of Cr.

Fabrication and characterization of ZnMgO nanowalls grown on 4H-SiC by molecular beam epitaxy

2019 ◽  
Vol 52 (1) ◽  
pp. 168-170
Author(s):  
Mieczyslaw A. Pietrzyk ◽  
Aleksandra Wierzbicka ◽  
Marcin Stachowicz ◽  
Dawid Jarosz ◽  
Adrian Kozanecki
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Optoelectronic Devices ◽  
Growth Conditions ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fabrication And Characterization

Control of nanostructure growth is a prerequisite for the development of electronic and optoelectronic devices. This paper reports the growth conditions and structural properties of ZnMgO nanowalls grown on the Si face of 4H-SiC substrates by molecular beam epitaxy without catalysts and buffer layers. Images from scanning electron microscopy revealed that the ZnMgO nanowalls are arranged in parallel rows following the stripe morphology of the SiC surface, and their thickness is around 15 nm. The crystal quality of the structures was evaluated by X-ray diffraction measurements.

Growth Conditions of Erbium-Oxygen-Doped Silicon Grown by MBE

1996 ◽  
Vol 422 ◽  
Author(s):  
J. Stimmer ◽  
A. Reittinger ◽  
G. Abstreiter ◽  
H. Holzbrecher ◽  
Ch. Buchal
Keyword(s):  
Molecular Beam Epitaxy ◽  
Systematic Study ◽  
Molecular Beam ◽  
Growth Parameters ◽  
Light Emitting Diode ◽  
Growth Conditions ◽  
Light Emitting ◽  
Doped Silicon

AbstractWe report on a systematic study of the growth parameters of erbium-oxygen-doped silicon grown by molecular beam epitaxy. The surface quality of the grown layers was measured in situ by RHEED. The samples were characterized by photoluminescence measurements and SIMS. An Er-O-doped Si light emitting diode grown with the optimized parameters is presented.

The use of NiMnSb Heusler alloy in MBE Grown Tunnel Junction

2001 ◽  
Vol 690 ◽  
Author(s):  
Pascal Turban ◽  
Stéphane Andrieu ◽  
Alberto Tagliaferri ◽  
Céline De Nadai ◽  
Nike Brookes
Keyword(s):  
Electronic Properties ◽  
Growth Process ◽  
Room Temperature ◽  
Molecular Beam ◽  
Magnetic Circular Dichroism ◽  
Growth Conditions ◽  
Photoemission Spectroscopy ◽  
Structural Quality ◽  
X Ray

ABSTRACTIn this paper, the structural, magnetic and electronic properties of single-crystalline NiMnSb thin films grown by molecular beam epitaxy are presented. The growth process and surface morphology were studied by RHEED and STM. The structural quality of the films was investigated by EXAFS and HRTEM. For the optimized growth conditions, the expected NiMnSb C1b structure was obtained. Moreover, the most stable surface was found to be 4x1 reconstructed. The magnetic and electronic properties were studied by X-ray magnetic circular dichroïsm and spin-resolved x-ray photoemission spectroscopy experiments. The magnetization was observed to be essentially due to Mn, in agreement with theory. The surface was not found to be fully polarized but a polarization near 50% at room temperature was observed. Finally, the preparation of fully epitaxial NiMnSb/MgO/NiMnSb(001) trilayers is presented.

In as a Surfactant for the Growth of AlGaN/GaN Heterostructures by Plasma Assisted MBE

2002 ◽  
Vol 743 ◽  
Author(s):  
E. Monroy ◽  
N. Gogneau ◽  
E. Bellet-Amalnc ◽  
F. Enjalbert ◽  
J. Barjon ◽  
...  
Keyword(s):  
Molecular Beam ◽  
Growth Conditions ◽  
Molecular Beam Epitaxy Growth ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Dimensional Growth

ABSTRACTIn this paper, we study the surfactant capability of In for the growth of AlGaN/GaN heterostructures by plasma-assisted molecular beam epitaxy. Growth conditions were determined to have a self-regulated 1×1 In adlayer on AlxGa1-xN (0001). The presence of this In film favors two dimensional growth of AlGaN under stoichiometric conditions, and inhibits the formation of metal droplets on the surface. The quality of these layers was assessed by high resolution X-ray diffraction, atomic force microscopy and photoluminescence.

scholarly journals Effect of Annealing on the Crystal Structure of COSI2/SI(100) Formed By MBE, SSE and RE Epitaxy Techniques

2019 ◽  
Vol 9 (1) ◽  
pp. 4813-4818
Keyword(s):  
Thin Film ◽  
Crystal Structure ◽  
Heat Treatment ◽  
Solid State ◽  
Molecular Beam ◽  
Growth Conditions ◽  
Cobalt Ions ◽  
State Diagrams ◽  
Silicon Doped

The paper reports a number of new original experimental results related to the study of the effect of annealing on the crystal structure of the surface of silicon doped with cobalt ions. The results of studies of the CoSi2 /Si(100) epitaxial structures formed by molecular beam epitaxy (MBE), solid state epitaxy (SSE), and other techniques are presented. Relations between morphology, stoichiometry, and growth conditions of CoSi2 / Si structures were established. The ratio of the intensities of the Auger signals of cobalt and silicon in the CoSi2 film, as well as silicon in CoSi2 and the silicon substrate was determined by the Auger profile of the sample. The authors determined that under certain conditions of heat treatment of the radiation on the surface of a single crystal, the so-called epitaxial silicides are formed which can play the role of conductive layers or metal coated. The structural state diagrams of CoSi2 / Si (100) thin-film systems formed by the MBE, SSE and other methods were compiled..

A Study of Low-Temperature Grown Gap by Gas-Source Molecular Beam Epitaxy

1996 ◽  
Vol 421 ◽  
Author(s):  
W. G. Bi ◽  
X. B. Mei ◽  
K. L. Kavanagh ◽  
C. W. Tu ◽  
E. A. Stach ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Flow Rate ◽  
Molecular Beam ◽  
Growth Conditions ◽  
Cross Sectional ◽  
Rocking Curve ◽  
Gas Source ◽  
Transmission Electron ◽  
Lt Gaas

AbstractWe report the effects of growth conditions on the strain and crystalline quality of lowtemperature (LT) grown GaP films by gas-source molecular beam epitaxy. At temperatures below 160 °C, poly-crystalline GaP films are always obtained, regardless of the PH3 low rate used, while at temperatures above 160 °C, the material quality is affected by the PH3 flow rate. Contrary to compressively strained LT GaAs, high-resolution X-ray rocking curve measurement indicates a tensile strain of the LT GaP films, which is considered to be due to PGa antisite defects. The strain is found to be affected by the PH3 flow rate, the growth temperature, and post-growth annealing. Contrary to LT GaAs, no P precipitates are observed in cross-sectional transmission electron microscopy.

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