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Quantum percolation transition in Eu 1− x Ca x B 6
Author(s) -
Glushkov V. V.,
Anisimov M. A.,
Bogach A. V.,
Demishev S. V.,
Filipov V. B.,
Flachbart K.,
Kuznetsov A. V.,
Levchenko A. V.,
Shitsevalova N. Yu.,
Sluchanko N. E.
Publication year - 2010
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200983044
Subject(s) - condensed matter physics , colossal magnetoresistance , ferromagnetism , percolation (cognitive psychology) , magnetoresistance , paramagnetism , percolation threshold , physics , magnetic field , chemistry , electrical resistivity and conductivity , quantum mechanics , neuroscience , biology
The study of transport and magnetic properties performed on Eu 1− x Ca x B 6 single crystals with nominal Ca content 0 ≤ x ≤ 0.4 at temperatures 1.8–300 K in magnetic fields up to 80 kOe provides the direct experimental evidence of metal‐to‐insulator transition (MIT) earlier proposed for the system by V. M. Pereira et al. [Phys. Rev. Lett., 93, 147202 (2004)]. A giant enhancement of magnetoresistance up to the values of ( ρ (0) − ρ ( H ))/ ρ ( H ) ∼ 7 × 10 7 % was detected for x = 0.4 in the wide vicinity of the ferromagnetic insulating state. The field induced crossover from hole‐like to electron‐like regime of charge transport observed for the first time in the paramagnetic phase of Eu 0.6 Ca 0.4 B 6 is discussed in terms of quantum percolation transition predicted for this low carrier density system within double exchange model.