Correlated giant dielectric peaks and antiferromagnetic transitions near room temperature in pure and alkali-doped BaMnO3-δ

O. B. Korneta, T. F. Qi, M. Ge, S. Parkin, L. E. De Long, P. Schlottmann, G. Cao

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

We report structural, magnetic, dielectric and thermal properties of single-crystal BaMnO2.99 and its derivatives BaMn 0.97Li0.03O3 and Ba0.97K 0.03MnO3. The hexagonal 15R-BaMnO2.99 perovskite phase is a known antiferromagnetic insulator that orders at a Néel temperature TN=220K. We find dilute Li and K doping change the ratio of cubic to hexagonal layers and cause drastic changes in the dielectric and magnetic properties. Unusually large high-temperature magnetoelectric shifts (up to 85%) are observed near temperatures at which pronounced peaks in the dielectric constant are observed for applied electric fields along either the cor a axis, respectively. The temperatures of the dielectric peaks are strongly correlated with anomalies in the c-or a-axis magnetic susceptibility and the specific heat for all compositions studied. All our data suggest that the strongly anisotropic magnetic and dielectric anomalies (which occur near, or above room temperature) originate from the same Mn ion sites, which implies these materials form an exceptional class of magnetoelectrics.

Original languageEnglish
Article number435901
JournalJournal of Physics Condensed Matter
Volume23
Issue number43
DOIs
StatePublished - Nov 2 2011

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics

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