front-matter
Lecture Notes in Physics
Springer
Spin Electronics
Foreword
Preface
Contents
Part I Introduction
Part II Basic Concepts
Part III Materials, Techniques and Devices
List of Contributors
Chapter 1
1 Introduction to Spin Electronics
1.1 Coey ’s Lemma
1.2 The Two Spin Channel Model
1.2.1 Spin Asymmetry
1.2.2 Spin Accumulation
1.2.3 Spin Diffusion Length
1.2.4 The Role of Impurities in Spin Electronics
1.2.5 How Long is the Spin Diffusion Length?
1.2.6 How Large is a Typical Spin Accumulation?
1.3 Two Terminal Spin Electronics
1.3.1 The Analogy with Polarized Light
1.3.2 Spin Tunneling Processes [15,16,17,18 ]
1.3.3 The Dominance of the Fermi Surface
1.3.4 CIP and CPP GMR [19 ]
1.4 Three Terminal Spin Electronics
1.5 Mesomagnetism
1.5.1 Giant Thermal Magnetoresistance
1.5.2 The Domain Wall in Spin Electronics
1.6 Hybrid Spin Electronics
1.6.1 The Monsma Transistor
1.6.2 Spin Transport in Semiconductors
1.6.4 Measuring Spin Decoherence in Semiconductors
1.6.5 How to Improve Direct Spin-Injection Efficiency
1.6.6 Novel Spin Transistor Geometries –Materials and Construction Challenges
1.7 The Rashba Effect and the Spin FET [47,48 ]
1.8 Refinements in the Understanding of Spin Tunneling
1.9 Methods for Measuring Spin Asymmetry
1.10 FSETs
1.10.1 Spin Blockade
1.11 Unusual Ventures in Spin Electronics.
1.12 The Future of Spin Electronics.
1.13 Acknowledgements
References
Chapter 2
2 An Introduction to the Theory of Normal and Ferromagnetic Metals
2.1 Introduction
2.2 What is a Metal ?
2.2.1 Definition of the Fermi Energy
2.2.2 Electron Energy Bands in Metals
2.2.3 Justification of the Independent Particle Model
2.2.4 Imperfect Crystals
2.3 Band Magnetism
2.3.1 Magnetic Susceptibility
2.3.2 Ordered Phases
2.3.3 Stoner Theory
2.3.4 Strong and Weak Ferromagnets
2.3.5 Excitations in Ferromagnets
2.3.6 The Phase Transition
2.3.7 Impurities in Nonmagnetic Metals
2.4 Strong Coupling Theories
2.4.1 Formation of Local Moments
2.4.2 Ordered Arrays of Moments
2.4.3 The Kondo Effect
2.4.4 Heavy Fermion Compounds
2.5 Problems
References
Chapter 3
3 Basic Electron Transport
3.1 Introduction
3.2 The Boltzmann Equation
3.3 The Relationship Between the Boltzmann Equation and the Kubo –Greenwood Formula
3.4 How the Energy and Momentum Relaxation Rates are Related
3.5 Thin Films and the Fuchs–Sondheimer Model
3.6 The Normal Magnetoresistance
3.7 Beyond the Boltzmann Theory: Quantum Interference Effects
3.8 Experimental Methods
3.8.1 Resistivity
3.8.2 Hall Effect and Thermopower
3.9 Problems
3.10 Solutions
Bibliography
References
Chapter 4
4 Phenomenological Theory of Giant Magnetoresistance
4.1 Introduction
4.2 Physical Origin of GMR
4.3 Spin Dependent Scattering of Electrons in Magnetic Multilayers
4.4 Resistor Network Theory of GMR
4.5 Exercises
References
Chapter 5
5 Electronic Structure, Exchange and Magnetism in Oxides
5.1 Introduction
5.2 Transition Metal Ions in Crystals
5.3 Orbital Degeneracy and Jahn–Teller Effect
5.4 Exchange Interaction in Magnetic Insulators
5.5 Charge-Transfer versus Mott–Hubbard Insulators
5.6 Goodenough–Kanamori–Anderson Rules
5.7 Exchange Mechanism of Orbital Ordering
5.8 Doping of Magnetic Insulators; Double Exchange
5.9 Concluding Remarks
References
Chapter 6
6 Transport Properties of Mixed-Valence Manganites
6.1 Electronic Structure
6.1.1 Ionic Model
6.1.2 Band Model
6.1.3 Phase Separation
6.2 Resistivity and Magnetoresistance
6.2.1 Variations with Doping Level
6.2.2 Temperature– and Field–Induced Resistive Transitions
6.2.3 Models for Electronic Transport
6.3 Applications
References
Chapter 7
7 Spin Dependent Tunneling
7.1 Introduction
7.2 Magnetic Junctions
7.2.1 Types of Junctions
7.2.2 Magnetic Properties
7.2.3 Problems
7.3 Magnetic Impurities
7.4 Magnetic Excitations
7.5 Magnetic Properties of the Interface
7.5.1 Problems
7.6 Charging Effects in Granular Systems
7.6.1 Problems
7.7 Conclusions
References
Chapter 8
8 Basic Semiconductor Physics
8.1 Introduction
8.1.1 What is a Semiconductor?
8.1.2 Simple Band Structure
8.2 Charge –Carrier Concentration,Band Gap and Fermi Energy
8.2.1 Intrinsic Semiconductors
8.2.2 P and N Type Doping
8.2.3 Impurity Bands
8.2.4Charge –Carrier Concentration and Fermi Energy of Extrinsic Semiconductors
8.3 Carrier Transport
8.3.1 Introduction
8.3.2 Drift Current and Mobility
8.3.3 Di .usion Current
8.3.4Mobility and Conductivity
8.3.5 Band Bending
8.4 P –N Junction
8.4.1 Barrier Potential
8.4.2 Depletion Zones
8.4.3 Varicap TM Diode or Varactor Diode
8.4.4 Light Emitting Diodes
8.5 Haynes –Shockley Experiment
8.6 Exercises
References
Chapter 9
9 Metal–Semiconductor Contacts
References
Chapter 10
10 Micromagnetic Spin Structure
10.1 Introduction
10.2 Intrinsic Properties
10.2.1 Magnetic Moment, Exchange, and Magnetization
10.2.2 Anisotropy
10.3 Basic Micromagnetism
10.3.1 Coherent Rotation
10.3.2 Domains and Domain Walls
10.3.3 Hysteresis and Coercivity
10.3.4 Time Dependence of Magnetic Properties
10.4 Grain –boundary Magnetism
10.4.1 Model
10.4.2 Boundary Conditions
10.4.3 Layer –Resolved Spin Structure
10.5 Concluding Remarks
Acknowledgement
References
Chapter 11
11 Electronic Noise in Magnetic Materials and Devices
11.1 Introduction
11.2 Mathematical Treatment
11.2.1 The Time Domain Analysis
11.2.2 The Fourier Analysis of the Fluctuating Quantity
11.3 The Most Common Types of Noise
11.3.1 Thermal Noise
11.3.2 Shot Noise
11.3.3 1 /f Noise
11.3.4 Non-Gaussian Noise and Random Telegraph Noise (RTN)
11.4 Electronic Noise Studies in Materials for Spin Electronic Applications
11.4.1 Low Frequency Noise in Half-Metallic Oxides
11.4.2 Electrical Noise in CMR Perovkites
11.4.3 Electrical Noise in GMR based sensors
11.5 Concluding Remarks
Acknowledgements
References
Chapter 12
12 Materials for Spin Electronics
12.1 Introduction
12.2 Iron Group Alloys
12.2.1 Iron–based Alloys
12.2.2 Nickel–based Alloys
12.2.3 Cobalt–based Alloys
12.3 Antiferromagnets
12.4 Oxides and Half–metals
12.5 Ferromagnetic Semiconductors
Problems
The Bibliography
References
Chapter 13
13 Thin Film Deposition Techniques (PVD)
13.1 Introduction
13.2 Thin Film Deposition Methods
13.2.1 Thermal Evaporation
13.2.2 Ion Plating
13.2.3 Molecular Beam Epitaxy (MBE)
13.2.4 Sputtering Methods
13.3 Thin Film Growth
13.3.1 Nucleation
13.3.2 Thornton Diagram
13.3.3 Epitaxial Growth
13.3.4 Reactive Deposition of Compounds
13.3.5 Bias Effects
References
Acknowledgement
Chapter 14
14 Magnetic Imaging
14.1 Introduction
14.2 Bitter Pattern Formation
14.3 Electron Microscopy
14.3.1 Transmission Electron Microscopy
14.3.2 Scanning Electron Microscopy (SEM)Techniques
14.4 Scanning Force Microscopy
14.4.1 Magnetic Force Microscopy
14.4.2 Atomic Force Microscopy
14.5 Polarised Light Microscopy
14.5.1 Magneto–Optical Kerr Effect Microscopy
14.5.2 New Developments in Kerr Microscopy
14.5.3 Polarised Light Microscopy: Advantages and Disadvantages
14.6 Summary
Acknowledgements
14.7 Problems
14.8 Solutions
References
Chapter 15
15 Observation of Micromagnetic Configurations in Mesoscopic Magnetic Elements
15.1 Introduction
15.2 Fabrication Methods of Nanomagnets
15.2.1 E-beam Lithography
15.2.2 X-ray Lithography
15.2.3 Electrodeposition Into Porous Templates
15.3 Magnetic Force Microscopy
15.3.1 Principle of the Magnetic Force Microscope
15.3.2 Modelling of the MFM Response
15.4 Micromagnetic Calculations
15.5 Domain Formation in Thin Films
15.5.1 Origin of Domains
15.5.2 Stripe Domains in Thin Films with Perpendicular Anisotropy
15.6 Micromagnetic Configurations in Mesoscopic Dots
15.6.1 Reduction of Lateral Sizes
15.6.2 Preparation
15.6.3 Domains in Perpendicular Dots: Effect of Thickness and Shape
15.6.4 Domains in Canted Dots
15.6.5 Domains in In-Plane Circular Dots
15.7 Domains in Circular Rings
15.7.1 Linear versus Circular Magnetization Mode
15.7.2 Magnetization Con .gurations in Submicron Rings
15.7.3 Metastable States Observed Using the MFM Tip Effect
15.7.4 Reversal Processes in Rings
15.8 Domain Configurations in Wires
15.8.1 Sample Preparation
15.8.2 Wires with Crystal Anisotropy Field Perpendicular to the Wire Axis
15.8.3 Crystal Anisotropy Field Parallel to the Wire Axis
15.9 Summary
15.10 Conclusion
Acknowledgments
References
Chapter 16
16 Micro– and Nanofabrication Techniques
16.1 How Can We Go from Magnetic Layers to Submicron Scale Devices?
16.2 Basic Processes
16.2.1 Standard Patterning
16.2.2 Lift–Off Patterning
16.3 Deposition Techniques
16.4 Resist Deposition
16.4.1 The Resists
16.4.2 Resist Deposition
16.5 Pattern Generation
16.5.1 Lithography Through a Mask
16.5.2 Direct Writing
16.5.3 Trilayer Technique
16.6 Etching of the Layers
16.6.1 Wet Etching
16.6.2 Ion Beam Etching–Ion Milling [3,23 ]
16.6.3 Reactive Ion Etching
16.6.4 Focused Ion Beam (FIB) Etching
16.7 Additional Techniques
16.7.1 AFM–STM Lithography
16.7.2 Chemical Transfer, Nanoimprint
References
Chapter 17
17 Spin Transport in Semiconductors
17.1 Introduction
17.2 Basics
17.3 Spin–Coherent Transport
17.4 Spin–Injection
17.4.1 Ferromagnetic Metallic Electrodes
17.4.2 Magnetic Semiconductors
17.5 Spin–Detection
17.6 Devices
17.6.1 The Datta and Das Transistor
17.6.2 The SPICE Transistor
17.6.3 The Hot–Electron Spin–Valve
17.7 Conclusions
Acknowledgement
References
Chapter 18
18 Circuit Theory for the Electrically Declined
18.1 The Soldering Iron and the Spin Electronician
18.2 Ohm ’s Lawand Simple DC Circuits
18.2.1 The Potential Divider
18.2.2 Voltage Sources
18.2.3 Current Sources
18.3 Norton –Thevenin Transforms
18.4 AC Circuit Theory
18.4.1 Transfer Functions
18.4.2 Norton –Thevenin Transforms Applied to AC Theory
18.5 Impedance Transformation
18.5.1 The Transformer and its Uses
18.5.2 Real (i.e.Imperfect)Transformers
18.6 The Ideal Operational Amplifier
18.6.1 Closed Loop Gain vs Open Loop Gain
18.7 Transistors –Howto Choose a Good One.
18.8 Small Signal Analysis Using Di .erential Calculus – the Physicist ’s Approach
18.8.1 Common Collector
18.9 Equivalent Circuits –the Engineer ’s Approach
18.9.1 Common Emitter Equivalent Circuit
18.9.2 Common Collector Equivalent Circuit
18.10 The Loadline and its Uses
18.11 Miller Effect
18.12 Nyquist Amplifier Stabilit Theory
18.12.1 Local and Non-local Feedback
18.13 Useful Circuit Tricks
18.13.1 Bootstrapping and the “Ring of Three ”
18.14 Noise
18.14.1 Johnson Noise
18.14.2 Shot Noise
18.15 The DC Motor
18.16 Acknowledgements
18.17 Concluding Remarks
Chapter 19
19 Spin–Valve and Spin–Tunneling Devices: Read Heads, MRAMs, Field Sensors
19.1 Read Heads and Magnetic Data Storage
19.1.1 Spin–Valve Sensors
19.2 Tunnel Junction Random Access Memories (TJMRAM)
19.3 Other Sensor Applications; Current Monitoring, Position Control, Bio–Molecular Recognition.
19.4 Conclusions
References
back-matter
Index