We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Vacancy defects and monopole dynamics in oxygen-deficient pyrochlores.
- Authors
Sala, G.; Porter, D. G.; Goff, J. P.; Gutmann, M. J.; Prabhakaran, D.; Pomaranski, D.; Mitchelitis, C.; Kycia, J. B.; Castelnovo, C.
- Abstract
The idea of magnetic monopoles in spin ice has enjoyed much success at intermediate temperatures, but at low temperatures a description in terms of monopole dynamics alone is insufficient. Recently, numerical simulations were used to argue that magnetic impurities account for this discrepancy by introducing a magnetic equivalent of residual resistance in the system. Here we propose that oxygen deficiency is the leading cause of magnetic impurities in as-grown samples, and we determine the defect structure and magnetism in Y2Ti2O7-δ using diffuse neutron scattering and magnetization measurements. These defects are eliminated by oxygen annealing. The introduction of oxygen vacancies causes Ti4+ to transform to magnetic Ti3+ with quenched orbital magnetism, but the concentration is anomalously low. In the spin-ice material Dy2Ti2O7 we find that the same oxygen-vacancy defects suppress moments on neighbouring rare-earth sites, and that these magnetic distortions markedly slow down the long-time monopole dynamics at sub-Kelvin temperatures.
- Subjects
MAGNETIC monopoles; COMPUTER simulation; MAGNETIC impurities; NEUTRON scattering; MAGNETIZATION; THERMOGRAVIMETRY
- Publication
Nature Materials, 2014, Vol 13, Issue 5, p488
- ISSN
1476-1122
- Publication type
Article
- DOI
10.1038/NMAT3924