1st Edition

Magnetic Anisotropies in Nanostructured Matter

By Peter Weinberger Copyright 2009
    328 Pages 119 B/W Illustrations
    by Chapman & Hall

    One of the Top Selling Physics Books according to YBP Library Services

    Magnetic Anisotropies in Nanostructured Matter presents a compact summary of all the theoretical means to describe magnetic anisotropies and interlayer exchange coupling in nanosystems. The applications include free and capped magnetic surfaces, magnetic atoms on metallic substrates, nanowires, nanocontacts, and domain walls. Some applications also deal with temperature-dependent effects and ab initio magnetization dynamics.

    The author clarifies parallel and antiparallel, the distinction between classical spin vectors and spinors, and the actual form of spin–orbit interactions, before showing how symmetry can provide the formal tools to properly define magnetic structures. After these introductory chapters, the book presents methods to describe anisotropic physical properties of magnetic nanostructures. It then focuses on magnetic anisotropy energies, exchange and Dzyaloshinskii–Moriya interactions, temperature-dependent effects, spin dynamics, and related properties of systems nanostructured in one and two dimensions. The book also discusses how methods of describing electric and magneto-optical properties are applied to magnetic nanostructured matter. It concludes with an outlook on emerging magnetic anisotrophic effects.

    Written by a leading researcher with over 35 years of experience in the field, this book examines the theory and modeling of magnetic anisotropies in nanostructured materials. It shows how these materials are used in a range of applications.

    Introduction

    Preliminary Considerations

    Parallel, antiparallel, collinear, and noncollinear

    Characteristic volumina

    "Classical" spin vectors and spinors

    The famous spin–orbit interaction

    Symmetry Considerations

    Translational invariance

    Rotational invariance

    Colloquial or parent lattices

    Tensorial products of spin and configuration

    Cell-dependent potentials and exchange fields

    Magnetic configurations

    Green’s Functions and Multiple Scattering

    Resolvents and Green’s functions

    The Dyson equation

    Scaling transformations

    Integrated density of states

    Superposition of individual potentials

    The scattering path operator

    Angular momentum and partial wave representations

    Single particle Green’s function

    Symmetry aspects

    Charge and magnetization densities

    Changing the orientation of the magnetization

    Screening transformations

    The embedded cluster method

    The Coherent Potential Approximation

    Configurational averages

    Restricted ensemble averages

    The coherent potential approximation

    The single-site coherent potential approximation

    Complex lattices and layered systems

    Remark with respect to systems nanostructured in two dimensions

    Calculating Magnetic Anisotropy Energies

    Total energies

    The magnetic force theorem

    Magnetic dipole–dipole interactions

    Exchange and Dzyaloshinskii–Moriya Interactions

    The free energy and its angular derivatives

    An intermezzo: classical spin Hamiltonians

    Relations to relativistic multiple scattering theory

    The Disordered Local Moment Method (DLM)

    The relativistic DLM method for layered systems

    Approximate DLM approaches

    Spin Dynamics

    The phenomenological Landau–Lifshitz–Gilbert equation

    The semiclassical Landau–Lifshitz equation

    Constrained density functional theory

    The semiclassical Landau–Lifshitz–Gilbert equation

    First principles spin dynamics for magnetic systems nanostructured in two dimensions

    The Multiple Scattering Scheme

    The quantum mechanical approach

    Methodological aspects in relation to magnetic anisotropies

    Physical properties related to magnetic anisotropies

    Nanostructured in One Dimension: Free and Capped Magnetic Surfaces

    Reorientation transitions

    Trilayers, interlayer exchange coupling

    Temperature dependence

    A short summary

    Nanostructured in One Dimension: Spin Valves

    Interdiffusion at the interfaces

    Spin valves and noncollinearity

    Switching energies and the phenomenological Landau–Lifshitz–Gilbert equation

    Heterojunctions

    Summary

    Nanostructured in Two Dimensions: Single Atoms, Finite Clusters, and Wires

    Finite clusters

    Finite wires and chains of magnetic atoms

    Aspects of noncollinearity

    Nanostructured in Two Dimensions: Nanocontacts, Local Alloys

    Quantum corrals

    Magnetic adatoms and surface states

    Nanocontacts

    Local alloys

    Summary

    A Mesoscopic Excursion: Domain Walls

    Theory of Electric and Magneto-Optical Properties

    Linear response theory

    Kubo equation for independent particles

    Electric transport—the static limit

    The Kubo–Greenwood equation

    Optical transport

    Electric Properties of Magnetic Nanostructured Matter

    The bulk anisotropic magnetoresistance (AMR)

    Current-in-plane (CIP) and the giant magnetoresistance (GMR)

    Current-perpendicular to the planes of atoms (CPP)

    Tunneling conditions

    Spin-valves

    Heterojunctions

    Systems nanostructured in two dimensions

    Domain wall resistivities

    Summary

    Magneto-Optical Properties of Magnetic Nanostructured Matter

    The macroscopic model

    The importance of the substrate

    The Kerr effect and interlayer exchange coupling

    The Kerr effect and magnetic anisotropy energy

    The Kerr effect in the case of repeated multilayers

    How surface sensitive is the Kerr effect?

    Summary

    Time Dependence

    Terra incognita

    Pump-probe experiments

    Pulsed electric fields

    Spin currents and torques

    Instantaneous resolvents and Green’s functions

    Time-dependent multiple scattering

    Physical effects to be encountered

    Expectations

    Afterword

    Index

    Biography

    Peter Weinberger