bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scanning Probe Techniques:
MFM
and
SP
‐
STM
Authors: Schwarz Alexander , Bode Matthias , Wiesendanger Roland 
Published: December 2007

Abstract
This chapter surveys the basic concepts, experimental conditions, modes of operation, tip preparation, and the contrast mechanisms of two magnetic‐sensitive scanning probe techniques, that is, magnetic force microscopy (MFM) and spin‐polarized scanning tunneling microscopy (SP‐STM). The strength and limitations of these imaging techniques are exemplified by presenting results obtained on numerous sample systems including magnetic hard disks, epitaxial surfaces, and nanoparticles at various temperatures and external fields.
Alternative Patterning Techniques: Magnetic Interactions in Nanomagnet Arrays
Authors: Ferré Jacques , Jamet Jean Pierre 
Published: December 2007

Abstract
Novel high‐resolution top‐down patterning techniques can be an alternative way to usual lithography fabrication methods for preparing arrays of quasi‐identical thin ferromagnetic nanoelements. One reports essentially on the following techniques: (i) ion beam lithography, (ii) direct writing by scanning a Ga focused ion beam (FIB), (iii) film deposition on prepatterned templates. The physical origin of soft magnetic patterning by He or Ga ions in thin‐film structures at low dose is discussed. All these techniques allow to prepare dense arrays of nanodots with negligible magnetic interaction that are among the best candidates for fabricating discrete perpendicular magnetic recording media with ultrahigh density. A review on advantages and limitations of studies of nanodot arrays is given. By increasing the Ga ion dose in narrow FIB lines separating ferromagnetic Pt/Co/Pt nanodots, the interdot magnetic interaction can be varied and controlled from exchange to dipolar. This gives the opportunity to study and analyze static and dynamic behavior of coupled macrospin assemblies.
Epitaxial Heusler Alloys onIII‐VSemiconductors
Authors: Hesjedal Thorsten , Ploog Klaus H. 
Published: December 2007

AbstractAt the basis of future applications of spin electronics are ferromagnetic films that have a Curie temperature above room temperature, a crystal structure that allows for epitaxial growth on common semiconductor surfaces, and a high degree of spin polarization at the Fermi level. A class of ternary compounds, the so‐called Heusler alloys, combine these requirements as they are lattice‐matched to many compound semiconductors, have a compatible crystal structure (face‐centered cubic), and show high Curie temperatures. Moreover, calculations suggested that some Heusler alloys may belong to the magnetic class of half‐metals that is characterized by a 100% spin polarization at the Fermi level. We review the work on epitaxial‐Heusler alloy films on semiconductor surfaces. Special emphasis is laid on molecular‐beam epitaxy (MBE), as this growth method allows for anin situcontrol of the growth and structure of the material. Taking Co2FeSi on GaAs as an example, the structural and magnetic properties of MBE‐grown samples will be discussed.
Soft Magnetic Materials—Nanocrystalline Alloys
Authors: Herzer Giselher 
Published: December 2007

Abstract
Nanocrystalline Fe‐based alloys combine the advantageous properties of various soft magnetic materials, that is, the high saturation induction of Fe‐based alloys, the high permeability and low magnetostriction of permalloys or amorphous Co‐based alloys and the favorable high‐frequency behavior of ferrites or amorphous metals. The materials to be highlighted are devitrified glassy Fe–Cu–Nb–Si–B alloys, which, owing to their outstanding properties, have meanwhile successfully entered into application. The microstructure consists of randomly oriented, about 10–15‐nm small bcc‐FeSi grains embedded in a ferromagnetic amorphous minority matrix. The article surveys the key factors from which the extraordinary properties of this new class of soft ferromagnets derive. Thus, the local magnetocrystalline anisotropies are largely averaged out since their orientation is randomly fluctuating on a scale much smaller than the domain wall width. The structural phases formed upon crystallization lead to a low or vanishing saturation magnetostriction. Like in other soft magnetic materials, annealing‐induced anisotropies finally allow to tailor the hysteresis loop according to the various demands of application.
Rare‐earth Nanocrystalline and Nanostructured Magnets
Authors: Marinescu Melania , Gabay Alexander , Hadjipanayis George C. 
Published: December 2007

AbstractThe contribution presents the recent advances in permanent magnets with nanocrystalline or nanophase structures based on rare‐earth compounds. The main classes of magnets discussed are the nanocrystalline single‐phase and nanocomposite R2Fe14B‐based magnets; nanocomposite Nd–Fe carbides; bulk‐hardened R2Co17and RCo5nanocrystalline magnets; Sm(Fe,M)12, SmFe3, and Sm5(Fe,M)17nanocrystalline magnets; Sm2Fe17nitrides and carbides; and Nd(Fe,M)12nitrides and carbides (R and M denotes rare‐earth elements and transition metals, respectively). The magnetic hardening mechanism and the relation with the particular morphologies (grain size and phase constitution) of the different types of nanocrystalline and nanostructured magnets are reviewed.
Heusler Alloys
Authors: de Groot Robert A. 
Published: December 2007

AbstractHalf‐metallic magnetism was discovered first in a Heusler C1b alloy. Since there is no simple univocal experiment to test for half‐metallicity, electronic structure calculations have played an important role in the discovery, explanation and prediction of half‐metals. Experimental work related to half‐metallicity is reviewed. Attention is given to the special role of surfaces and interfaces. Half‐metallic anti‐ferromagnetism (100% spin‐polarization without a magnetization) is discussed. Finally, the computational and experimental status of heusler L21 alloys is summarized.
Ferrimagnetic Insulators
Authors: Brabers Victor A.M. 
Published: December 2007

Abstract

Ferrimagnetic insulators
Most of the useful ferrimagnetic insulators are found in the mixed oxide systems with a high concentration of iron, the so‐called ferrites, which show at room temperature a substantial magnetization and makes them suitable for a large variety of applications. Soft magnetic ferrites are usually encountered in the spinel and garnet structure ferrites, whereas hard‐magnetic ferrites crystallize in a hexagonal structure. A short discussion is presented of the various types of ferrites in addition to a more extended presentation of the more recent developments about the properties of magnetite, Fe
3
O
4
.

In particular the mechanism of the electronic structure and the mechanism of the electrical conduction as well as the mechanism of the Verwey transition are discussed because of the importance and possibilities of Fe
3
O
4
in spintronic applications.
Template‐based Synthesis and Characterization of High‐density Ferromagnetic Nanowire Arrays
Authors: Nielsch Kornelius , Stadler Bethanie J. H. 
Published: December 2007

AbstractThis chapter covers the synthesis and characterization of magnetic nanowire arrays that are grown inside nanoporous templates. Applications for such arrays include patterned recording media, magnetic and acoustic sensors, and other avant‐garde applications that will be envisioned once the fundamental properties and performances of these arrays are better known. Several nanoporous templates are introduced, but this chapter primarily focuses on results using anodic alumina templates. The templates are filled with ferromagnetic metals via electrodeposition either using DC deposition onto an electrode after the removal of a barrier oxide or using AC deposition to eliminate the need to remove the oxide. Several typical electrolyte recipes are given (Co, Fe, FeGa alloys, Ni, and NiMn), and the details of both techniques are discussed. Methods for controlling the magnetic properties of the arrays by the choice of nanowire material, diameter, and interpore spacing, in addition to external fields, are detailed. Next, numerical simulations are presented in order to investigate the switching behavior of magnetic nanowires. Perfect hexagonal arrangements of pores on a square centimeter scale are demonstrated using imprint lithography. Finally, the applications of recording and sensors are discussed in detail.
Hard Magnetic Films
Authors: Shima Toshiyuki , Takanashi Koki 
Published: December 2007

Abstract

Hard magnetic films, showing high magnetocrystalline anisotropy, have been attracting much attention recently for application to magnetic devices since the critical grain size for superparamagnetic limit can be reduced to the nanometer scale. In this chapter, the fabrication techniques and the magnetic properties of hard magnetic films are reviewed. Firstly, the fundamental phenomena and models which are important for the understanding of hard magnetic properties in thin films are described. Secondly, the recent developments of hard magnetic films and their potential applications are mentioned. Particularly the relationship between micro‐/nanostructure and the magnetization process (coercivity mechanism) is discussed in detail for rare earth–transition metal alloy films and L1
0
‐ordered FePt films.
Molecular Nanomagnets
Authors: Wernsdorfer Wolfgang 
Published: December 2007

AbstractMolecular nanomagnets (or single‐molecule magnets (SMMs)) have attracted much interest in recent years both from experimental and theoretical points of view. These systems are organometallic clusters characterized by a large‐spin ground state with a predominant uniaxial anisotropy. The quantum nature of these systems makes them very appealing for phenomena occurring on the mesoscopic scale, that is, at the boundary between classical and quantum physics. Below their blocking temperature, they exhibit magnetization hysteresis, the classical macroscale property of a magnet, as well as quantum tunneling of magnetization (QTM) and quantum phase interference, the properties of a microscale entity. QTM is advantageous for some potential applications of SMMs, for example, in providing the quantum superposition of states for quantum computing, but it is a disadvantage in others such as information storage. It is widely accepted that SMMs have a potential for quantum computation, in particular, because they are extremely small and almost identical, allowing to obtain, in a single measurement, statistical averages of a larger number of qubits. This chapter introduces a few basic concepts that are needed to understand the quantum phenomena observed in molecular nanomagnets and it concludes by mentioning new trends of the field of molecular nanomagnets toward molecular spintronics.
Ferromagnetic Manganite Films
Authors: Moshnyaga Vasily , Samwer Konrad 
Published: December 2007

Abstract

We discuss the structure and electronic properties of ferromagnetic perovskite manganites with general formula Re

1−
x

Ae

x

MnO
3
(Re = La, Pr, Nd and Ae = Ca, Sr, Ba). These magnetic oxides being strongly correlated electronic systems show metal‐insulator and ferro‐paramagnetic phase transitions as well as charge/orbital ordering. Moreover, competition among charge, spin, and lattice degrees of freedom can lead to mesoscopic electronic inhomogeneity known also as electronic phase separation. Focusing on the magnetotransport properties in thin manganite films, we will show how the fundamental phenomena mentioned in the preceding text interplayed with specific thin‐film‐related characteristics like epitaxy stress, growth mode, and microstructure, govern various magnetoresistance (MR) effects—colossal magnetoresistance (CMR), tunneling, and anisotropic MR.
Spin‐dependent Tunneling: Role of Evanescent and Resonant States
Authors: Tsymbal Evgeny Y. 
Published: December 2007

Abstract

There are two important factors which control the spin polarization of the tunneling current in epitaxial magnetic tunnel junctions (MTJs), in addition to the bulk band structure of ferromagnetic electrodes: evanescent states in the insulating barrier and the electronic structure of the ferromagnet/barrier interface. We consider several theoretical models illustrating the significance of these two factors in different kinds of MTJs. Symmetry of the evanescent states in the barrier selects those spin‐polarized bands in the ferromagnetic electrodes that are able efficiently tunnel through the barrier. This mechanism is responsible for large values of tunneling magnetoresistance (TMR) predicted and observed in crystalline MTJs based on an MgO insulating barrier and for the negative spin polarization of Co/SrTiO
3
/Co MTJs with bcc Co electrodes. The interface bonding may result in the appearance of interfaces resonant states that dramatically affect the spin polarization of the tunneling current. These states explain a decrease of TMR in Fe/MgO/Fe(001) MTJs for small barrier thickness. The presence of an interface band at the oxidized Co(001) surface causes the spin polarization of the tunneling current across vacuum to be negative, as opposed to that predicted for the clean Co surface. The strong interface bonding between Co and O atoms at the interface in Co/Al
2
O
3
/Co MTJs explains positive values of the spin polarization observed experimentally.
Diluted Ferromagnetic Semiconductors—Theoretical Aspects
Authors: Dietl Tomasz 
Published: December 2007

Abstract

This chapter reviews theoretical understanding of ferromagnetic response that has been detected in diluted magnetic semiconductors (DMS). Particular attention is paid to those ferromagnetic DMS in which
no
precipitation of other crystallographic phases has been observed. It is argued that these materials can be divided into three categories. The first consists of (Ga,Mn)As, heavily doped p‐(Zn,Mn)Te, and related compounds. In these solid solutions, the theory built on p–d Zener's model of hole‐mediated ferromagnetism and on either the Kohn‐Luttinger
kp
theory or the multiorbital tight‐binding approach describes qualitatively, and often quantitatively, thermodynamic, micromagnetic, optical, and transport properties. Moreover, the understanding of these materials has provided a basis for the development of novel methods enabling magnetization manipulation and switching. To the second group, belong compounds in which a competition between long‐range ferromagnetic and short‐range antiferromagnetic interactions and/or the proximity of the localization boundary lead to an electronic nanoscale phase separation that results in characteristics similar to colossal magnetoresistance oxides. Finally, in a number of compounds a chemical nanoscale phase separation into the regions with small and large concentrations of the magnetic constituent is present. Methods of controlling the spinodal decomposition and possible functionalities of these systems are outlined.
Spin‐transfer in High Magnetic Fields and Single Magnetic Layer Nanopillars
Authors: Kent Andrew D. 
Published: December 2007

Abstract

This chapter reviews studies of the physics of spin transfer in high magnetic fields in bilayer and single magnetic layer nanopillars. The focus is on phenomena associated with the action of spin currents on the background magnetization of thin nanometer‐scale ferromagnetic layers, known as
nanomagnets
. Spin currents are shown to lead to magnetic hysteresis in large fields perpendicular to the layers in bilayer nanopillars. This is consistent with the standard model of spin transfer within a macrospin approximation. Spin‐transfer‐induced excitations also occur in single magnetic layer nanopillars. This shows that the most elementary samples that exhibit spin transfer consist of just a single thin magnetic layer, not two magnetic layers. Physics beyond the macrospin and one‐dimensional transport models is necessary to understand such excitations. Nonuniform spin‐wave excitations are also seen in the traditional bilayer structures, which experiments reveal to have a rich phase diagram of current‐induced magnetic excitations.
Electrical Double Layers: Theory and Simulations
Authors: Schmickler Wolfgang 
Published: December 2007

Abstract
The sections in this article are

Introduction

Gouy–Chapman Theory and its Extensions

Theoretical Methods and Principles of Computer Simulations

Integral Equations

Computer Simulations

Monte Carlo simulations

Molecular Dynamics

Car–Parinello Method

Electronic Structure Calculations

Models for the Solution

Field‐Theoretical Approach to the Double Layer

Ensembles of Hard Spheres

The Role of the Metal

Qualitative Considerations

The Jellium Model

Calculations for Metal Clusters

The Metal–Solution Interface

Jellium in Contact with Model Solutions

Molecular Dynamics Simulations

Car–Parinello‐Type Simulations

Rough Electrodes

Liquid–Liquid Interfaces

Verwey–Niessen Theory

Capillary Waves

Lattice Gas Model

Conclusion

Acknowledgments
Phase Transitions in Two‐dimensional Adlayers at Electrode Surfaces: Thermodynamics, Kinetics, and Structural Aspects
Authors: Wandlowski Thomas 
Published: December 2007

AbstractThe sections in this article areIntroductionThermodynamic AspectsPhase Transitions and Order ParameterAdsorption Isotherms and Lateral InteractionsKinetics of 2DPhase Formation and DissolutionDiffusion, Adsorption, AutocatalysisNucleation and Growth MechanismsNucleationGrowthCoupling of Nucleation and GrowthDissolution of 2DCondensed MonolayersExamplesPhase Transitions in Anionic AdlayersIntroductionPhase Formation in Halide AdlayersPhase Transitions in Adlayers of OxoanionsPhase Transitions inUPD—AdlayersIntroductionUnderpotential Deposition of Copper Ions onAu(hkl)Underpotential Deposition of Copper Ions onPt(hkl)Underpotential Deposition of Lead onAg(hkl)Phase Transitions in Organic MonolayersGeneral AspectsThermodynamic AspectsKinetic AspectsCase Study I—Coumarin at the Mercury–Aqueous Electrolyte InterfaceCase StudyIII—2,2′‐Bipyridine (2,2′‐BP) onAu(hkl)Conclusion and OutlookAcknowledgment
In
s
itu
FTIR
as a Tool for Mechanistic Studies. Fundamentals and Applications
Authors: Nart Francisco C. , Iwasita Teresa 
Published: December 2007

Abstract
The sections in this article are

Historical Overview

The External Reflectance Spectroscopy

Fundamentals

The Band Intensity

Surface Selection Rule

Experimental Setup

Transport Effects in the Thin Electrolyte Film

Infrared Spectroscopy under Equilibrium Conditions. Study of Adsorbed Sulfate Ions on Single‐crystal Electrode Surfaces

The Adsorption of Anions (The Electrical Double Layer)

The Adsorption of Sulfate on
M
(111) Single‐crystal Electrodes

The Sulfate Ion Adsorbed on the
M
(100) and (110) Single‐crystal Electrodes

Infrared Spectroscopy under Nonequilibrium Conditions. Study of Systems Relevant in Electrocatalysis

Carbon Monoxide

Adsorption and Oxidation of
CO
on Polycrystalline Substrates

Adsorption and Oxidation of
C
O on Single‐crystal Substrates

Methanol

Ethanol

Potential Dependence of the Band Intensities

Final remarks

Acknowledgments

Appendix
Linear Sweep and Cyclic Voltammetry
Authors: Speiser Bernd 
Published: December 2007

Abstract
The sections in this article are

Introduction

Historical Background

Potential Scan Voltammetries—Definitions

Scope of the Chapter

Theory of Potential Scan Voltammetries

General

Reversible Electron Transfer

Kinetics of Electron Transfer

Coupled Homogeneous Chemical Kinetics

Adsorption and Surface‐Bound Redox Species

Nonlinear Diffusion

Restricted Diffusion

Simulation

Practical Considerations

Electrodes and Cells

Solvents and Supporting Electrolytes

Experimental Limitations

Artifacts and how to Avoid Them

Present Methodological Developments

Voltammetry at Ultramicroelectrodes

Fast Scan Techniques

Voltammetry without Supporting Electrolyte

Voltammetry Under Hydrodynamic Conditions

Voltammetric Spectroelectrochemistry

Derivative Voltammetry

Semiintegral (“Convolution”) and Semiderivative Voltammetry

Applications

Typical Voltammograms—Classical Applications

Selected Recent Examples

Conclusion

Acknowledgments
Hydrodynamic Electrodes
Authors: Mount Andrew R. 
Published: December 2007

Abstract
The sections in this article are

Introduction

Rotating Disc Hydrodynamics

Rotating Disc Electrode (
RDE
)

The Rotating Ring Disc Electrode (
RRDE
)

The Optical Rotating Disc Electrode (
ORDE
)

Solution Flow Hydrodynamic Systems

The Wall‐tube Electrode (
WTE
)

The Wall‐jet Electrode (
WJE
)

The Wall‐jet Ring‐disc Electrode (
WJRDE
)

The Tube or Tubular Electrode (
TE
)

The Channel Electrode (
CE
)

The Double Channel Electrode (
DCE
) and Double Tube Electrode (
DTE
)

Numerical Calculations

Microhydrodynamic Systems
Biosensors
Authors: Schuhmann Wolfgang , Bonsen Eva Maria 
Published: December 2007

Abstract
The sections in this article are

Introduction

Basic Principles and Setup

Application of Biosensors. Principal Considerations

Biorecognition Elements

Catalytic Biorecognition Elements

Bioaffinity Recognition Elements

Transducers and Instrumentation

Amperometric Electrodes

Potentiometric Sensors

Conductometric and Impedimetric Transducers

Coupling of Biorecognition Elements and Transducers

Specific Features of Electrochemical Biosensors

Amperometric Biosensors

Shuttle Mechanism Using Free‐diffusing Natural Redox Mediators

Artificial Redox Compounds as Free‐diffusing Electron‐Transfer Mediators

Immobilized Redox Mediators—“Electroenzymes”

“Wired” Enzymes by Means of Redox Hydrogels

Conducting Polymers

Direct Electron Transfer between Redox Enzymes and Electrodes

Potentiometric Biosensors

Potentiometric Enzyme Biosensors

Potentiometric Immunosensors

Field‐effect Transistors

Conductometric and Impedimetric Biosensors

Miniaturization and Future Aspects

Miniaturized Transducers

Advantages and Problems of Miniaturized Biosensors

Multisensor Arrays and Sensor Chips
Crevice Corrosion
Authors: Kelly Robert G. 
Published: December 2007

Abstract
The sections in this article are

Definition of Crevice Corrosion

Characteristics

Relation to Other Forms of Localized Corrosion

Examples

Fundamental Phenomena of Crevice Corrosion

Electrochemical Reactions

Dissolution Reactions

Cathodic Reactions

Separation of Anodic and Cathodic Reactions

Area Effects

Homogeneous Chemical Reactions

Hydrolysis

Precipitation

Chemical Dissolution of Alloy Constituents

Mass Transport of Species

Migration

Diffusion

Convection

Range of Rates and Limitations by Each Process

Proposed Mechanisms

Critical Crevice Solution

Ohmic Drop

Combining Effects

Scaling Relations in Crevice Corrosion

Prevention

By Geometry

By Flow

By Material Selection

By Inhibition

By Potential Control
Corrosion Protection by Metallic Coatings
Authors: Plieth Waldfried , Bund Andreas 
Published: December 2007

Abstract
The sections in this article are

Introduction

Principles of Electrochemical Metal Deposition

Principles of Alloy Deposition

Role of Additives

Mechanisms of Corrosion Protection by Metallic Coatings

Pretreatment of the Base Metal

Mechanical Pretreatment

Chemical Pretreatment

Examples

Zinc/Cadmium

Zinc

Cadmium

Copper/Nickel

Copper

Nickel

Nickel‐phosphorus

Electroless Copper and Nickel

Hard and Decorative Chromium Coatings

Corrosion Protection of Copper/Nickel/Chromium Layers

Tin

Noble Metals

Silver

Gold

Platinum Metals

Alloys

Zinc‐cobalt

Zinc‐iron

Zinc‐nickel

Zinc‐manganese

Tin‐zinc

Nickel‐iron

Intrinsically Conducting Polymers (
ICP
’
s
, “Synthetic Metals”)

Application of Intrinsically Conducting Polymers to a Metal Surface

Mechanism of Corrosion Protection by Intrinsically Conducting Polymers

Aluminum

Posttreatment

Wax, Lacquer, Paint

Conversion Coatings

Conclusion
Microbiologically Influenced Corrosion
Authors: Little Brenda J. , Mansfeld Florian B. , Arps Peggy J. , Earthman James C. 
Published: December 2007

AbstractThe sections in this article areBiofilm FormationCorrosion Promoting MechanismsSulfur, Sulfate and Thiosulfate ReductionPractical AspectsSulfur/Sulfide OxidationMetal‐oxidizing BacteriaMetal‐reducing BacteriaAcid‐producing OrganismsSlime‐producing BacteriaCorrosion Inhibiting Mechanisms