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 language | English (US) |
|---|---|
| Pages (from-to) | 4789-4807 |
| Number of pages | 19 |
| Journal | Physical Review B |
| Volume | 9 |
| Issue number | 11 |
| DOIs | |
| State | Published - 1974 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Condensed Matter Physics
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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 journal › Article
}
TY - JOUR
T1 - Fine-structure splitting of a localized moment in a metal
T2 - A diagrammatic analysis
AU - Barnes, Stewart
PY - 1974
Y1 - 1974
N2 - 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.
AB - 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.
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U2 - 10.1103/PhysRevB.9.4789
DO - 10.1103/PhysRevB.9.4789
M3 - Article
AN - SCOPUS:0010010656
VL - 9
SP - 4789
EP - 4807
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 1098-0121
IS - 11
ER -