Doping dependence of polaron hopping energies in La1-x Cax MnO3 (0≤x≤0.15)

K. P. Neupane, J. L. Cohn, H. Terashita, J. J. Neumeier

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

Measurements of the low-frequency (f≤100 kHz) permittivity at T 160 K and dc resistivity (T 430 K) are reported for La1-x Cax MnO3 (0≤x≤0.15). Static dielectric constants are determined from the low- T limiting behavior of the permittivity. The estimated polarizability for bound holes ∼ 10-22 cm-3 implies a radius comparable to the interatomic spacing, consistent with the small polaron picture established from prior transport studies near room temperature and above on nearby compositions. Relaxation peaks in the dielectric loss associated with charge-carrier hopping yield activation energies in good agreement with low- T hopping energies determined from variable-range hopping fits of the dc resistivity. The doping dependence of these energies suggests that the orthorhombic, canted antiferromagnetic ground state tends toward an insulator-metal transition that is not realized due to the formation of the ferromagnetic insulating state near Mn4+ concentration ≈0.13.

Original languageEnglish (US)
Article number144428
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume74
Issue number14
DOIs
StatePublished - 2006

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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