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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 ,
M. Uehara ,
M. E. Gershenson ,
T. Y. Koo  and
S-W. Cheong
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
Information
MRS Online Proceedings Library (OPL) , Volume 602: Symposium JJ – Magnetoresistive Oxides & Related Materials , 1999 , 113
Copyright
Copyright © Materials Research Society 2000

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