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

Abstract

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 themore » 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/.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
TRIUMF and Department of Physics, University of British Columbia, Vancouver, B.C., Canada V6T 2A3
OSTI Identifier:
5923140
Resource Type:
Journal Article
Journal Name:
Phys. Rev. B: Condens. Matter; (United States)
Additional Journal Information:
Journal Volume: 35:13
Country of Publication:
United States
Language:
English
Subject:
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-)

Citation Formats

Noakes, D R, Brewer, J H, Harshman, D R, Ansaldo, E J, and Huang, C Y. Electron, muon, and nuclear spin dynamics in SmRh/sub 4/B/sub 4/ and ErRh/sub 4/B/sub 4/. United States: N. p., 1987. Web. doi:10.1103/PhysRevB.35.6597.
Noakes, D R, Brewer, J H, Harshman, D R, Ansaldo, E J, & Huang, C Y. Electron, muon, and nuclear spin dynamics in SmRh/sub 4/B/sub 4/ and ErRh/sub 4/B/sub 4/. United States. doi:10.1103/PhysRevB.35.6597.
Noakes, D R, Brewer, J H, Harshman, D R, Ansaldo, E J, and Huang, C Y. Fri . "Electron, muon, and nuclear spin dynamics in SmRh/sub 4/B/sub 4/ and ErRh/sub 4/B/sub 4/". United States. doi:10.1103/PhysRevB.35.6597.
@article{osti_5923140,
title = {Electron, muon, and nuclear spin dynamics in SmRh/sub 4/B/sub 4/ and ErRh/sub 4/B/sub 4/},
author = {Noakes, D R and Brewer, J H and Harshman, D R and Ansaldo, E J and Huang, C Y},
abstractNote = {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/.},
doi = {10.1103/PhysRevB.35.6597},
journal = {Phys. Rev. B: Condens. Matter; (United States)},
number = ,
volume = 35:13,
place = {United States},
year = {1987},
month = {5}
}