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Title: Percolation theory and quantum critical systems: A new description of the critical behavior in Ce(Ru{sub 0.24}Fe{sub 0.76}){sub 2}Ge{sub 2}

The onset of ordering in quantum critical systems is characterized by a competition between the Kondo shielding of magnetic moments and the ordering of these moments. We show how a distribution of Kondo shielding temperatures—resulting from chemical doping—leads to critical behavior whose main characteristics are given by percolation physics. With the aid of Monte Carlo computer simulations, we are able to infer the low temperature part of the distribution of shielding temperatures in heavily doped quantum critical Ce(Ru{sub 0.24}Fe{sub 0.76}){sub 2}Ge{sub 2}. Based on this distribution, we show that the ordering dynamics—such as the growth of the correlation length upon cooling—can be understood by the spawning of magnetic clusters. Our findings explain why the search for universal exponents in quantum critical systems has been unsuccessful: the underlying percolation network associated with the chemical doping of quantum critical systems has to be incorporated in the modeling of these quantum critical systems.
Authors:
 [1] ;  [2] ;  [1] ;  [3]
  1. Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211 (United States)
  2. Missouri Research Reactor, University of Missouri, Columbia, Missouri 65211 (United States)
  3. (United States)
Publication Date:
OSTI Identifier:
22273923
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 17; Conference: 55. annual conference on magnetism and magnetic materials, Atlanta, GA (United States), 14-18 Nov 2010; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CERIUM COMPOUNDS; COMPUTERIZED SIMULATION; CORRELATIONS; DOPED MATERIALS; GERMANIDES; IRON COMPOUNDS; KONDO EFFECT; MAGNETIC MOMENTS; MONTE CARLO METHOD; RUTHENIUM COMPOUNDS