Fine-structure splitting of a localized moment in a metal: A diagrammatic analysis

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Abstract

Beginning with a generalized s-d Hamiltonian and including a term which induces electron-lattice relaxation, the Abrikosov fermion representation of spins and the Feynman-diagram technique are used to investigate the dynamics of localized moments. The analysis is performed for arbitrary spin, and in the presence of a fine-structure splitting of the localized-moment resonance by the crystalline field. A set of coupled linear equations is obtained which determines the macroscopic dynamic transverse susceptibility and which, under certain circumstances, is equivalent to a set of 2S+1 coupled Bloch-type equations. These equations are analyzed in some detail for the high-temperature regime kT SgsμBH0. In contrast to the case of the hyperfine splitting of a localized moment, it is found that the Korringa process alone leads to a narrowing of the resonance linewidth, even in the absence of a bottleneck. However, when the bottleneck is present, these narrowing processes are even larger. For a reasonable value of the exchange constant, it is at least qualitatively possible to explain the anisotropic behavior observed in recent electron-spin-resonance experiments of Mg:Gd alloys in terms of unresolved fine structure.

Original languageEnglish (US)
Pages (from-to)4789-4807
Number of pages19
JournalPhysical Review B
Volume9
Issue number11
DOIs
StatePublished - 1974
Externally publishedYes

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Metals
fine structure
moments
Hamiltonians
Fermions
Linear equations
Linewidth
metals
Paramagnetic resonance
Feynman diagrams
linear equations
Crystalline materials
Electrons
electron paramagnetic resonance
fermions
magnetic permeability
Experiments
Temperature
electrons

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Fine-structure splitting of a localized moment in a metal : A diagrammatic analysis. / Barnes, Stewart.

In: Physical Review B, Vol. 9, No. 11, 1974, p. 4789-4807.

Research output: Contribution to journalArticle

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