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Low-Temperature Permittivity of Insulating Perovskite Manganites

J. L. Cohn·M. Peterca·J. J. Neumeier
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Abstract

Measurements of the low-frequency (f<=100 kHz) permittivity and conductivity at T<= 150 K are reported for La(1-x)Ca(x)MnO(3) (0<=x<=1) and Ca(1-y)Sr(y)MnO(3) (0<=y<=0.75) having antiferromagnetic, insulating ground states covering a broad range of Mn valencies from Mn(3+) to Mn(4+). Static dielectric constants are determined from the low-T limiting behavior. With increasing T, relaxation peaks associated with charge-carrier hopping are observed in the real part of the permittivities and analyzed to determine dopant binding energies. The data are consistent with a simple model of hydrogenic impurity levels and imply effective masses m*/m_e~3 for the Mn(4+) compounds. Particularly interesting is a large dielectric constant (~100) associated with the C-type antiferromagnetic state near the composition La(0.2)Ca(0.8)MnO(3).

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J. L. Cohn, M. Peterca, J. J. Neumeier. 2004-10-26. Low-Temperature Permittivity of Insulating Perovskite Manganites. https://doi.org/10.1103/physrevb.70.214433

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