Influence of Layer Structure on Antiferromagnetic Exchange Coupling of Iron Films through Chromium Interlayers

1991 ◽  
Vol 231 ◽  
Author(s):  
A.P. Payne ◽  
H. Kataoka ◽  
M. Farle ◽  
B.M. Clemens
Keyword(s):  
Layer Structure ◽  
Buffer Layers ◽  
Antiferromagnetic Coupling ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Iron Films ◽  
Saturation Field ◽  
Topographic Roughness ◽  
Measure Surface Roughness ◽  
Sputtering Pressure

AbstractThe effect of layer structure perturbations on antiferromagnetic coupling in Fe-Cr-Fe trilayer systems is investigated. By varying the sputtering pressure, the layer structure of Fe-Cr-Fe trilayers is systematically altered, as indicated by changes in the low angle superlattice spectra of multilayers fabricated under identical conditions. The effect of topographic roughness is investigated by fabricating identical trilayers on Cr buffer layers of different thickness. Scanning tunneling microscopy is used to measure surface roughness. In each case the saturation field is measured as a function of Cr interlayer thickness by means of tapered Cr interlayer structures in which the thickness of the spacer varies linearly from 0 to 28 Å upon a single substrate. Antiferromagnetic coupling is measured locally by means of the magneto-optic Kerr effect. Results show that although the coupling is diminished by structural perturbations, it is a remarkably robust effect which persists even in instances of poor layer structure.

scholarly journals Surface Transport Properties of Pb-Intercalated Graphene

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7706
Author(s):  
Markus Gruschwitz ◽  
Chitran Ghosal ◽  
Ting-Hsuan Shen ◽  
Susanne Wolff ◽  
Thomas Seyller ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Defects ◽  
Interface Layer ◽  
Epitaxial Graphene ◽  
Buffer Layers ◽  
Scanning Tunneling ◽  
Large Area ◽  
Tunneling Microscopy ◽  
Surface Transport ◽  
Static Distortion

Intercalation experiments on epitaxial graphene are attracting a lot of attention at present as a tool to further boost the electronic properties of 2D graphene. In this work, we studied the intercalation of Pb using buffer layers on 6H-SiC(0001) by means of electron diffraction, scanning tunneling microscopy, photoelectron spectroscopy and in situ surface transport. Large-area intercalation of a few Pb monolayers succeeded via surface defects. The intercalated Pb forms a characteristic striped phase and leads to formation of almost charge neutral graphene in proximity to a Pb layer. The Pb intercalated layer consists of 2 ML and shows a strong structural corrugation. The epitaxial heterostructure provides an extremely high conductivity of σ=100 mS/□. However, at low temperatures (70 K), we found a metal-insulator transition that we assign to the formation of minigaps in epitaxial graphene, possibly induced by a static distortion of graphene following the corrugation of the interface layer.

Scanning tunneling microscopy of Pt/Co multilayers on Pt buffer layers

1991 ◽  
Vol 59 (22) ◽  
pp. 2898-2900 ◽  
Author(s):  
S. L. Tang ◽  
P. F. Carcia ◽  
D. Coulman ◽  
A. J. McGhie
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Buffer Layers ◽  
Scanning Tunneling ◽  
Tunneling Microscopy

Giant Magnetoresistance and Soft Magnetic Properties of NiFeCo/Cu Multilayers

1993 ◽  
Vol 313 ◽  
Author(s):  
S. Tsunashima ◽  
M. Jimbo ◽  
T. Kanda ◽  
S. Goto ◽  
S. Uchiyama
Keyword(s):  
Magnetic Properties ◽  
Giant Magnetoresistance ◽  
Layer Structure ◽  
Structural Characteristics ◽  
Buffer Layers ◽  
Antiferromagnetic Coupling ◽  
Soft Magnetic Properties ◽  
Transmission Electron Micrograph ◽  
Soft Magnetic ◽  
Cross Sectional

ABSTRACTGiant Magnetoresistance (GMR) and soft magnetic properties together with their structural characteristics were investigated for Ni66Fe16Co18/Cu Multilayers. The Multilayers were prepared by the conventional rf sputtering method on glass or Si substrates using various buffer layers including Fe, NiFeCo, NiFe and CoZr. Although Most of the multilayers exhibited (111) preferred orientation, Fe buffered multilayers showed a considerable (200) X-ray diffraction peak at Cu thicknesses around 1 nm and 2.2 nm which corresponded to the peak positions of GMR. By using fee or amorphous underlayers the (200) diffraction intensity decreased while antiferromagnetic coupling strength was much reduced. Cross-sectional transmission electron micrograph revealed that the (100) oriented multilayer was grown on the (100) oriented Fe underlayer. By controlling the crystal orientation and the layer structure, significantly large magnetoresistance ratio of more than 10 % can be achieved in a field as low as 30 Oe.

scholarly journals Growth of a self-assembled monolayer decoupled from the substrate: nucleation on-command using buffer layers

2020 ◽  
Vol 11 ◽  
pp. 1291-1302
Author(s):  
Robby Reynaerts ◽  
Kunal S Mali ◽  
Steven De Feyter
Keyword(s):  
Buffer Layer ◽  
Self Assembly ◽  
Network Formation ◽  
The Self ◽  
Buffer Layers ◽  
Scanning Tunneling ◽  
Structural Polymorphism ◽  
Tunneling Microscopy ◽  
Self Assembled Monolayer ◽  
Self Assembled

Structural polymorphism is ubiquitous in physisorbed self-assembled monolayers formed at the solution–solid interface. One of the ways to influence network formation at this interface is to physically decouple the self-assembled monolayer from the underlying substrate thereby removing the influence of the substrate lattice, if any. Here we show a systematic exploration of self-assembly of a typical building block, namely 4-tetradecyloxybenzoic acid at the 1-phenyloctane–graphite interface in the presence and in the absence of a buffer layer formed by a long chain alkane, namely n-pentacontane. Using scanning tunneling microscopy (STM), three different structural polymorphs were identified for 4-tetradecyloxybenzoic acid at the 1-phenyloctane–graphite interface. Surprisingly, the same three structures were formed on top of the buffer layer, albeit at different concentrations. Systematic variation of experimental parameters did not lead to any new network in the presence of the buffer layer. We discovered that the self-assembly on top of the buffer layer allows better control over the nanoscale manipulation of the self-assembled networks. Using the influence of the STM tip, we could initiate the nucleation of small isolated domains of the benzoic acid on-command in a reproducible fashion. Such controlled nucleation experiments hold promise for studying fundamental processes inherent to the assembly process on surfaces.

scholarly journals Morphology and structure of bright electrodeposited metal coatings

2011 ◽  
Vol 30 (1) ◽  
pp. 29
Author(s):  
Miomir G. Pavlović ◽  
Ljubica J. Pavlović
Keyword(s):  
Metal Surfaces ◽  
Layer Structure ◽  
Scanning Tunneling ◽  
Mirror Reflection ◽  
Tunneling Microscopy ◽  
Metal Coatings ◽  
Copper Surfaces ◽  
Copper Coatings ◽  
Electrodeposited Metal ◽  
High Degree

The properties which determine whether the metal surface is mirror bright are precisely determined by scanning electron microscopy (SEM), atomic forces microscopy (AFM), scanning tunneling microscopy (STM) and reflectance spectrophotometry investigations. Mirror brightness of metal surfaces can be associated with the high degree of mirror reflection which approaches very nearly the ideal reflectance of the same metal with the lowest degree of diffuse reflection. Mirror brightness of the copper coatings and the copper surfaces polished both mechanically and electrochemically was determined by flat and mutually parallel parts of the surface, which are smooth on the atomic level and which point out towards layer structure of these surfaces. Mirror bright metal surfaces can be obtained only by electrochemical polishing or electrochemical deposition in the presence of brightening addition agents.

Electronic Structure of Layered and Linear Chain Materials by Scanning Probe Microscopy

1994 ◽  
Vol 332 ◽  
Author(s):  
R.V. Coleman ◽  
Z. Dai ◽  
Y. Gong ◽  
C.G. Slough ◽  
Q. Xue
Keyword(s):  
Transition Metal ◽  
Layer Structure ◽  
Linear Chain ◽  
Density Wave ◽  
Spin Density Wave ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Metal Impurities ◽  
Transition Metal Impurities

ABSTRACTTransition metal impurities such as Fe, Ni, and Co can be intercalated into the van der Waals gap of layer structure dichalcogenides and these modify the charge-density wave (CDW) structure and CDW energy gaps. Ordered superlattices associated with antiferromagnetic phases can be detected by both scanning tunneling microscopy (STM) and atomic force microscopy (AFM). STM spectroscopy indicates the formation of a mixed spin-density-wave (SDW) and CDW (SDWCDW) in the doped materials. The quasi-one dimensional trichalcogenide NbSe3 exhibits two CDW transitions and the presence of dilute transition metal impurities produces ordered superlattices due to long range screening of the impurities.

Atiomiic Scale Interface Structure of In0.2Ga0.8As/GaAs Strained Layers Studied by Crosssectional Scanning Tunneijng Microscopy

1993 ◽  
Vol 319 ◽  
Author(s):  
J. F. Zheng ◽  
M. B. Salmeron ◽  
E. R. Weber
Keyword(s):  
Molecular Beam ◽  
Layer Structure ◽  
Growth Direction ◽  
Interface Roughness ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Strained Layers ◽  
Group Iii ◽  
Scale Fluctuation

AbstractA molecular beam epitaxy-grown In0.2Ga0.8As/GaAs strained layer structure has been studied by scanning tunneling microscopy in cross-section on the (110) cleavage plane perpendicular to [001] the growth direction. Individual Indium atoms were differentially imaged in the group III sublattice, allowing a direct observation of the interface roughness due to the indium compositional fluctuation. In the In0.2Ga0.8As layers, Indium atoms are found in clusters preferentially along the growth direction with each cluster containing 2-3 indium atoms. Indium segregation induced asymmetrical interface broadening is studied on an atomic scale. The interface of In0.2Ga0.8As grown on GaAs is sharp within 2-4 atomic layers. The interface of GaAs grown on In0.2Ga0.8As is found to be broadened to about 5-10 atomic layers. The atomic scale fluctuation due to indium distribution is about 20 Å along the interface in this case. We conclude that clustering and segregation are the main reason for the In0.2Ga0.8As/GaAs interface roughness.

STM studies of crystal growth

1991 ◽  
Vol 49 ◽  
pp. 374-375
Author(s):  
M. G. Lagally
Keyword(s):  
Crystal Growth ◽  
Molecular Beam ◽  
Chemical Vapor ◽  
Sputter Deposition ◽  
Field Of View ◽  
Scanning Tunneling ◽  
Wide Field ◽  
Tunneling Microscopy ◽  
Wide Field Of View ◽  
The One

It has been recognized since the earliest days of crystal growth that kinetic processes of all Kinds control the nature of the growth. As the technology of crystal growth has become ever more refined, with the advent of such atomistic processes as molecular beam epitaxy, chemical vapor deposition, sputter deposition, and plasma enhanced techniques for the creation of “crystals” as little as one or a few atomic layers thick, multilayer structures, and novel materials combinations, the need to understand the mechanisms controlling the growth process is becoming more critical. Unfortunately, available techniques have not lent themselves well to obtaining a truly microscopic picture of such processes. Because of its atomic resolution on the one hand, and the achievable wide field of view on the other (of the order of micrometers) scanning tunneling microscopy (STM) gives us this opportunity. In this talk, we briefly review the types of growth kinetics measurements that can be made using STM. The use of STM for studies of kinetics is one of the more recent applications of what is itself still a very young field.

Resolution in the scanning tunneling microscope

1991 ◽  
Vol 49 ◽  
pp. 488-489
Author(s):  
R. J. Wilson ◽  
D. D. Chambliss ◽  
S. Chiang ◽  
V. M. Hallmark
Keyword(s):  
Scanning Tunneling Microscope ◽  
Fundamental Principle ◽  
Atomic Scale ◽  
Lateral Resolution ◽  
Scanning Tunneling ◽  
Electronic Noise ◽  
Vertical Resolution ◽  
Tunneling Microscopy ◽  
Spatial Profile ◽  
Theoretical Analyses

Scanning tunneling microscopy (STM) has been used for many atomic scale observations of metal and semiconductor surfaces. The fundamental principle of the microscope involves the tunneling of evanescent electrons through a 10Å gap between a sharp tip and a reasonably conductive sample at energies in the eV range. Lateral and vertical resolution are used to define the minimum detectable width and height of observed features. Theoretical analyses first discussed lateral resolution in idealized cases, and recent work includes more general considerations. In all cases it is concluded that lateral resolution in STM depends upon the spatial profile of electronic states of both the sample and tip at energies near the Fermi level. Vertical resolution is typically limited by mechanical and electronic noise.

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