Colossal Effects in Transition Metal Oxides Caused by Intrinsic Inhomogeneities
Abstract
The influence of quenched disorder on the competition between ordered states separated by a first-order transition is investigated. A phase diagram with features resembling quantum-critical behavior is observed, even using classical models. The low-temperature paramagnetic regime consists of coexisting ordered clusters, with randomly oriented order parameters. Extended to manganites, this state is argued to have a colossal magnetoresistance effect. A scale T* for cluster formation is discussed. This is the analog of the Griffiths temperature, but for the case of two competing orders, producing a strong susceptibility to external fields. Cuprates may have similar features, compatible with the large proximity effect of the very underdoped regime.
- Publication:
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Physical Review Letters
- Pub Date:
- December 2001
- DOI:
- arXiv:
- arXiv:cond-mat/0107300
- Bibcode:
- 2001PhRvL..87A7202B
- Keywords:
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- Condensed Matter - Strongly Correlated Electrons;
- Condensed Matter - Superconductivity
- E-Print:
- 4 pages, 4 figures