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Giant 1/f Noise in Low-Tc CMR Manganites: Evidence of the Percolation Threshold

Published online by Cambridge University Press:  10 February 2011

V. Podzorov
Affiliation:
Serin Physics Laboratory, Rutgers University, Piscataway, NJ 08854-8019
M. Uehara
Affiliation:
Serin Physics Laboratory, Rutgers University, Piscataway, NJ 08854-8019
M. E. Gershenson
Affiliation:
Serin Physics Laboratory, Rutgers University, Piscataway, NJ 08854-8019
T. Y. Koo
Affiliation:
Bell Labs, Lucent Technologies, Murray Hill, NJ 07974
S-W. Cheong
Affiliation:
Serin Physics Laboratory, Rutgers University, Piscataway, NJ 08854-8019 Bell Labs, Lucent Technologies, Murray Hill, NJ 07974
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Abstract

We observed a dramatic peak in the 1/f noise at the metal-insulator transition (MIT) in low-Tc, manganites. This many-orders-of-magnitude noise enhancement is observed for both polycrystalline and single-crystal samples of La5/8−y. Pry, Ca3/8MnO3 (y = 0.35 – 0.4) and Pr1−xCaxMnO3 (x = 0.35 – 0.5). This observation strongly suggests that the microscopic phase separation in the low-Tc, manganites causes formation of a percolation network, and that the observed MIT is a percolation threshold. It is shown that the scale of phase separation in polycrystalline samples is much smaller than that in single crystals.

Type
Research Article
Copyright
Copyright © Materials Research Society 2000

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