Multiferroicity and magnetoelectric coupling in α-CaCr2O4

Abstract

Ferroelectricity in the incommensurate helical magnetic phase (below TN, 43K) of alpha CaCr2O4 has been confirmed by pyroelectric measurements. Magnetoelectric and magnetodielectric coupling exist below TN and are proportional to the square of magnetic field. From symmetry analysis, we suggest that the presence of an external electric field destabilizes the symmetrical 2221' phase and stabilizes 21' symmetry. This provides a unique system in which polarization varies as the fourth-degree of the order-parameter amplitude and exhibit a vanishingly small value below the first-order transition at TN, as observed experimentally.

14 pages, 4 figures

References in corpus (5)

• Ferroelectric polarization flop in a frustrated magnet MnWO${}_4$ induced by magnetic fields
• Spin-driven ferroelectricity and possible antiferroelectricity in triangular lattice antiferromagnets ACrO2 (A = Cu, Ag, Li, or Na)
• Multiferroicity with high-Tc in ceramics of the YBaCuFeO5 ordered perovskite
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• Exciton-magnon transitions in the frustrated chromium antiferromagnets CuCrO2, alpha-CaCr2O4, CdCr2O4, and ZnCr2O4
• The origin of up-up-down-down magnetic order in Cu${}_2$GeO${}_4$
• Raman study of magnetic excitations and magneto-elastic coupling in alpha-SrCr2O4
• Multiferroicity in Geometrically Frustrated α-MCr_2O_4 systems (M=Ca, Sr, Ba)
• Interpretation of magnetoelectric phase states using the praphase concept and exchange symmetry