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Colossal Effects in Transition Metal Oxides Caused by Intrinsic Inhomogeneities

J. Burgy·M. Mayr·V. Martin-Mayor·A. Moreo·E. Dagotto
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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.

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J. Burgy, M. Mayr, V. Martin-Mayor, A. Moreo, E. Dagotto. 2002-10-01. Colossal Effects in Transition Metal Oxides Caused by Intrinsic Inhomogeneities. https://doi.org/10.1103/physrevlett.87.277202

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