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Anomalous percolation and quantum criticality in diluted rare-earth nickelates

J. V. Alvarez·H. Rieger·A. Zheludev
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Abstract

A microscopic model for the diluted spin-mixed compounds (R_xY_(1-x))_2BaNiO_5 (R=magnetic rare-earth) is studied using Quantum Monte Carlo (QMC). The ordering temperature is shown to be a universal function of the impurity concentration x and the intrinsic Ni-chain correlation length. An effective model for the critical modes is derived. The possibility of a quantum critical point driven by the rare earth-concentration and the existence of a Griffiths phase in the high dilution limit is investigated. Several possible experimental approaches to verify the results are put forward.

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J. V. Alvarez, H. Rieger, A. Zheludev. 2004-01-11. Anomalous percolation and quantum criticality in diluted rare-earth nickelates. https://doi.org/10.1103/physrevlett.93.156401

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