Electron, muon, and nuclear spin dynamics in SmRh/sub 4/B/sub 4/ and ErRh/sub 4/B/sub 4/

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

DOI:https://doi.org/10.1103/PhysRevB.35.6597· OSTI ID:5923140

Noakes, D R; Brewer, J H; Harshman, D R; Ansaldo, E J; Huang, C Y

Zero-field positive muon spin relaxation (ZF-..mu../sup +/SR) studies of SmRh/sub 4/B/sub 4/ and ErRh/sub 4/B/sub 4/ have revealed several features of magnetic moment dynamics in these magnetic superconductors. The shape of the ..mu..SR signal is not simple over most of the temperature range studied in either SMRh/sub 4/B/sub 4/ or ErRh/sub 4/B/sub 4/ because of the complicated nature of both materials. In SmRh/sub 4/B/sub 4/ above 200 K we observe complete decoupling of the muon spins from the stable, localized samarium ionic moments due to the extremely fast fluctuation of those moments; below 200 K there is a nearly simultaneous onset of coupling of the samarium electronic moments to both the muon spins and the /sup 11/B nuclear moments. The muon spin-relaxation rate in SmRh/sub 4/B/sub 4/ increases smoothly as the temperature is lowered through the superconducting transition toward the antiferromagnetic ordering at 0.87 K. In ErRh/sub 4/B/sub 4/ the muon spin-relaxation function is a sum of two exponentials down to 50 K, below which the relaxation becomes too fast to be detected by our instruments, leaving only a signal of much-reduced amplitude at lower temperatures. We attribute the two exponentials to two distinct types of muon site in the crystal structure: a (high rms field) channel structure around the rare earths, and a (low rms field) site at the center of the RhB cluster. The deduced fluctuation rates of the rare-earth dipole fields at the muons are generally consistent with a model of paramagnetic rare-earth fluctuation mechanisms (Ruderman-Kittel-Kasuya-Yosida, Korringa, and spin-lattice interactions) above 4 K in SmRh/sub 4/B/sub 4/ and above 50 K (i.e., where the signal is fully resolved) in ErRh/sub 4/B/sub 4/.

• Research Organization: TRIUMF and Department of Physics, University of British Columbia, Vancouver, B.C., Canada V6T 2A3
• OSTI ID: 5923140
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Vol. 35:13
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ERBIUM BORIDES
MUON PROBES
SPIN-SPIN RELAXATION
RHODIUM BORIDES
SAMARIUM BORIDES
ANTIFERROMAGNETISM
ORDER PARAMETERS
RELAXATION TIME
SUPERCONDUCTORS
BORIDES
BORON COMPOUNDS
ERBIUM COMPOUNDS
MAGNETISM
PROBES
RARE EARTH COMPOUNDS
REFRACTORY METAL COMPOUNDS
RELAXATION
RHODIUM COMPOUNDS
SAMARIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties
360202 - Ceramics
Cermets
& Refractories- Structure & Phase Studies
656002 - Condensed Matter Physics- General Techniques in Condensed Matter- (1987-)