Magnetism and the Weiss Exchange Field - A Theoretical Analysis Inspired by Recent Experiments

Abstract

The huge spin precession frequency observed in recent experiments with spin-polarized beams of hot electrons shot through magnetized films is interpreted as being caused by Zeeman coupling of the electron spins to the so-called Weiss exchange field in the film. A "Stern-Gerlach experiment" for electrons moving through an inhomogeneous exchange field is proposed. The microscopic origin of exchange interactions and of large mean exchange fields, leading to different types of magnetic order, is elucidated. A microscopic derivation of the equations of motion of the Weiss exchange field is presented. Novel proofs of the existence of phase transitions in quantum XY-models and antiferromagnets, based on an analysis of the statistical distribution of the exchange field, are outlined.

arXiv comment36 pages, 3 figures

References in corpus (11)

• Enhanced Gilbert Damping in Thin Ferromagnetic Films
• Ferromagnetism in the Hubbard Model-- Examples from Models with Degenerate Single-Electron Ground States
• Nonrelativistic effective Lagrangians
• Ferromagnetism in the Hubbard model: A constructive approach
• Another Return of 'Return to Equilibrium'
• Effective Hamiltonians and Phase Diagrams for Tight-Binding Models
• Interaction Of Electrons With Spin Waves In The Bulk And In Multilayers
• KMS, etc
• Quantum Theory of Large Systems of Non-Relativistic Matter
• Hund's rule and metallic ferromagnetism
• Renormalization Group Methods: Landau-Fermi Liquid and BCS Superconductor

Cited by in corpus (6)

• Random loop representations for quantum spin systems
• Statistical Mechanics and the Physics of the Many-Particle Model Systems
• Scattering theory for Lindblad master equations
• Quantum Griffiths inequalities
• Gauge Invariance and Anomalies in Condensed Matter Physics
• Phase Transitions, Spontaneous Symmetry Breaking, and Goldstone's Theorem