Observation of a multiferroic critical end point

Wook Kim Jae, S. Y. Haam, Y. S. Oh, S. Park, S. W. Cheong, P. A. Sharma, M. Jaime, N. Harrison, Hoon Han Jung, Gun Sang Jeon, P. Coleman, Hoon Kim Kee

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

The study of abrupt increases in magnetization with magnetic field known as metamagnetic transitions has opened a rich vein of new physics in itinerant electron systems, including the discovery of quantum critical end points with a marked propensity to develop new kinds of order. However, the electric analogue of the metamagnetic critical end point, a "metaelectric" critical end point, has been rarely studied. Multiferroic materials wherein magnetism and ferroelectricity are cross-coupled are ideal candidates for the exploration of this novel possibility using magnetic-field (H) as a tuning parameter. Herein, we report the discovery of a magnetic-field-induced metaelectric transition in multiferroic BiMn2O5, in which the electric polarization (P) switches polarity along with a concomitant Mn spin-flop transition at a critical magnetic field Hc. The simultaneous metaelectric and spin-flop transitions become sharper upon cooling but remain a continuous cross-over even down to 0.5 K. Near the P = 0 line realized at μ0Hc ≈18 T below 20 K, the dielectric constant (ε) increases significantly over wide field and temperature (T) ranges. Furthermore, a characteristic power-law behavior is found in the P(H) and ε(H) curves at T = 0.66 K. These findings indicate that a magnetic-field-induced metaelectric critical end point is realized in BiMn 2O5 near zero temperature.

Original languageEnglish
Pages (from-to)15573-15576
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Volume106
Issue number37
DOIs
StatePublished - 15 Sep 2009

Keywords

  • BiMnO
  • Metaelectric transition
  • Spin-flop transition

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