FUNDAMENTALS OF MAGNETISM
CONTENTS INTRODUCTION FUNDAMENTAL TERMS CLASSI?CATION OF MAGNETIC MATERIAL BOHR–VAN LEEUWEN THEOREM MAGNETISM OF ATOMS ATOMS IN A MAGNETIC FIELD ATOMIC DIAMAGNETISM ATOMIC PARAMAGNETISM HUND’S RULES FOR THE GROUND STATE OF ATOMS PROBLEMS SOLID STATE MAGNETISM MODEL OF FREE ELECTRONS PAULI PARAMAGNETISM SPONTANEOUSLY SPIN SPLIT STATES MAGNETISM OF 3D TRANSITION METALS AND ALLOYS MAGNETIC INTERACTIONS MAGNETIC DIPOLE INTERACTION DIRECT EXCHANGE INDIRECT EXCHANGE COLLECTIVE MAGNETISM FERROMAGNETISM ANTIFERROMAGNETISM FERRIMAGNETISM HELICAL ORDER SPIN GLASSES BROKEN SYMMETRY BREAKING OF THE SYMMETRY DI?ERENT MODELS OF MAGNETIC BEHAVIOR CONSEQUENCES PHASE TRANSITIONS MAGNETIC EXCITATIONS MAGNETIC ANISOTROPY E?ECTS OVERVIEW OF MAGNETIC ANISOTROPIES MAGNETO CRYSTALLINE ANISOTROPY SHAPE ANISOTROPY INDUCED MAGNETIC ANISOTROPY STRESS ANISOTROPY (MAGNETOSTRICTION) MAGNETIC SURFACE AND INTERFACE ANISOTROPIES MAGNETIC DOMAIN STRUCTURES MAGNETIC DOMAINS DOMAIN WALLS DOMAIN WALL WIDTH CLOSURE DOMAINS MAGNETIZATION DYNAMICS MAGNETIC AFTER-E?ECT IN?UENCE OF HIGH-FREQUENT MAGNETIC FIELDS DAMPING PROCESSES FERROMAGNETIC RESONANCE MAGNETISM IN REDUCED DIMENSIONS – ATOMS 10 1 SINGLE ATOMS ON A SURFACE 10 2 QUANTUM MIRAGE 10 3 REVERSAL OF THE SPIN IN A SINGLE ATOM 10 4 IN?UENCE OF THE SUBSTRATE MAGNETISM IN REDUCED DIMENSIONS – CLUSTERS 11 1 “EVERY ATOM COUNTS” 11 2 IN?UENCE OF THE GEOMETRICAL ARRANGEMENT AND SURFACE SYMMETRY 11 3 CLUSTERS AT STEP EDGES 11 4 COMPARISON BETWEEN FREE AND SUPPORTED CLUSTERS MAGNETISM IN REDUCED DIMENSIONS – NANOPARTICLES 12 1 MAGNETIC DOMAINS OF NANOPARTICLES 12 2 SIZE DEPENDENCE OF MAGNETIC DOMAIN FORMATION 12 3 RING STRUCTURES 12 4 MAGNETIC VORTICES 12 5 SINGLE DOMAIN PARTICLES 12 6 SUPERPARAMAGNETISM OF NANOPARTICLES 12 7 MAGNETISM OF FREE NANOPARTICLES 12 8 NANOPARTICLES IN CONTACT WITH SURFACES 12 9 WET CHEMICALLY PREPARED NANOPARTICLES MAGNETISM IN REDUCED DIMENSIONS – NANOSCALED WIRES 13 1 WIRES EXHIBITING A WIDTH IN THE SUB-MICROMETER REGIME 13 2 WIRES CONSISTING OF SINGLE ATOMS MAGNETISM IN REDUCED DIMENSIONS – SINGLE THIN FILMS 14 1 SINGLE THIN FILM ON A SUBSTRATE 14 2 IN?UENCE OF A (NON-MAGNETIC) CAPPING LAYER 14 3 IN?UENCE OF A MAGNETIC CAPPING LAYER 14 4 COMPARISON BETWEEN AN IDEAL AND REAL INTERFACE 14 5 EXCHANGE BIAS MAGNETISM IN REDUCED DIMENSIONS – MULTILAYERS 15 1 INTERLAYER EXCHANGE COUPLING (IEC) ACROSS A NON-MAGNETIC SPACER LAYER 15 2 INTERLAYER EXCHANGE COUPLING ACROSS AN ANTIFERROMAGNETIC SPACER LAYER 15 3 IN?UENCE OF THE INTERFACE ROUGHNESS ON THE IEC 15 4 “SPIN ENGINEERING” BY INTERLAYER EXCHANGE COUPLING 15 5 SPIN VALVES 15 6 ADDITIONAL TYPES OF COUPLING MAGNETORESISTIVITY 16 1 NORMAL MAGNETORESISTANCE 16 2 AMR – ANISOTROPIC MAGNETORESISTANCE 16 3 GMR – GIANT MAGNETORESISTANCE 16 4 CMR – COLOSSAL MAGNETORESISTANCE 16 5 TMR – TUNNELLING MAGNETORESISTANCE APPLICATIONS 17 1 MRAM – MAGNETIC RANDOM ACCESS MEMORY 17 2 READ HEADS IN HARD DISKS 17 3 SENSORS SOLUTIONS