Contents

• 1. Introduction
  • 1.1 Magnetic nanotechnology and magnetic nanostructures
  • 1.2 Magnetic recording crisis and challenges
  • 1.3 The role of numerical modeling
  
  
• 2. Numerical methods: towards multiscale description
  • 2.1 Multiscale character of magnetism
  • 2.2 Linking different spatial scales
    • 2.2.1 Ab-initio calculation of magnetic properties.
    • 2.2.2 Atomistic models in magnetism
    • 2.2.3 Micromagnetics: classical approach to model magnetization distribution
    • 2.2.4 Passing atomistic information to micromagnetics: a multiscale model^2.1
  • 2.3 Linking different timescales
    • 2.3.1 The magnetization dynamics and the Landau-Lifshitz-Gilbert equation
    • 2.3.2 Non-thermal adiabatic approximation^2.3
    • 2.3.3 Short-time thermal description: stochastic LLG equations
    • 2.3.4 Long-time behavior: Arrhenius-Néel law
    • 2.3.5 Monte Carlo methods
    • 2.3.6 Energy barriers calculations^2.4
    • 2.3.7 Acceleration methods: Victora and Voter methods
    • 2.3.8 Victora method^2.5
    • 2.3.9 Voter method^2.6
  
  
• 3. Multiscale modeling of magnetization reversal in soft/hard bilayer for magnetic recording applications
  • 3.1 Introduction
  • 3.2 Theoretical background
  • 3.3 Atomistic models
  • 3.4 Simulations of one grain of FePt/FeRh
  • 3.5 Coercivity reduction in FePt/FeRh film: necessity of multiscale modeling
  • 3.6 Multigrain FePt/FeRh material
  • 3.7 Magnetization dynamics of an FePt/FeRh bilayer
  • 3.8 Generic Soft/Hard material: one grain simulation
  • 3.9 Energy barriers of individual grains
  • 3.10 Multigrain simulations in generic soft/hard magnetic material
  • 3.11 Figures of merit
  • 3.12 Conclusions
  • 3.13 Conclusiones en castellano
  
  
• 4. Magnetization reversal in textured Fe particles with different aspect ratios
  • 4.1 Experimental motivation
  • 4.2 Simulational model
  • 4.3 Magnetization reversal in ideal Fe elongated particles
  • 4.4 Angular dependence of coercivity
  • 4.5 Coercivity of Fe particles with surface anisotropy
  • 4.6 Coercivity of Fe particles with magnetoelastic anisotropy
  • 4.7 Thermal switching mechanism in Fe particles
  • 4.8 Conclusions
  • 4.9 Conclusiones en castellano
  
  
• 5. Modeling of hysteresis processes in antidot Fe films
  • 5.1 Introduction
  • 5.2 Coercivity dependence on the geometrical parameters
    • 5.2.1 Experimental results
    • 5.2.2 Previous simulations
    • 5.2.3 Damaged zone simulations
  • 5.3 Angular dependence of coercivitiy
    • 5.3.1 Experimental Results
    • 5.3.2 Coherent Reversal Model
    • 5.3.3 Periodic Model
    • 5.3.4 Domain Wall Model
  • 5.4 Conclusions
  • 5.5 Conclusiones en castellano
  
  
• Bibliography