Relaxation of nuclear and electronic magnetic moments in heavy-electron compounds

Journal Article · Fri May 01 04:00:00 EDT 1987 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.35.6504· OSTI ID:6057532

Cox, D L

Estimates are presented of nuclear-spin-lattice relaxation rates in the normal state of heavy-electron metals due to dipolar coupling of nuclear moments and 4f or 5f spin fluctuations. The 4f or 5f sites are modeled as point ions in the LS limit with dynamics of the N/sub grd/-fold degenerate Anderson model. Dipolar coupling alone is sufficiently large to account for the relaxation of /sup 9/Be in CeBe/sub 13/ and UBe/sub 13/, as has been found for other light nuclei in heavy-electron and local moment systems. However, for heavy nuclei with large intrinsic relaxation rates due to stronger on-site coupling to conduction electrons, the dipolar contribution underestimates the observed relaxation by orders of magnitude. I suggest that nuclear resonance is a more effective probe than electron-spin resonance of the heavy-fermion state primarily because the probe nuclei sit closer to the heavy-electron sites so that the strong range dependence of both dipolar and transferred exchange (Ruderman-Kittel-Kasuya-Yosida) interactions favors nuclear relaxation. I show for the Anderson lattice, using both mean field formalism and Green's function formalism (the latter explicitly including dynamic many-body effects and assuming a dispersionless interaction contribution to the f-electron self-energy) that many-body cancellation effects are relevant in magnetic relaxation in heavy-electron compounds only when coupling of probe moments to distant heavy-electron sites is vanishingly small.

• Research Organization: Physics Department, B019, University of California, San Diego, La Jolla, California 92093
• OSTI ID: 6057532
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 35:13; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
ACTINIDE ALLOYS
ALLOYS
BERYLLIUM ALLOYS
CERIUM ALLOYS
DISTANCE
ELECTRON SPIN RESONANCE
FUNCTIONS
GREEN FUNCTION
INTERACTION RANGE
KONDO EFFECT
MAGNETIC MOMENTS
MAGNETIC RESONANCE
MANY-BODY PROBLEM
MEAN-FIELD THEORY
NUCLEAR MAGNETIC RESONANCE
RARE EARTH ALLOYS
RELAXATION
RESONANCE
SPIN-LATTICE RELAXATION
URANIUM ALLOYS