Symmetry and coupling of magnetic and electric order parameters in YMnO3

Lottermoser, Thomas; Fiebig, Manfred; Fröhlich, D.

doi:10.1063/1.1448790

Cited by 6 publications

(2 citation statements)

References 8 publications

(11 reference statements)

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“…Here, we investigate electric-field poling at the nanometer scale in hexagonal YMnO 3 . In this material, uniform tilting of the MnO 5 bipyramids in the unit cell and a concomitant shift of the yttrium ions occur at 1258 K. This lattice-trimerizing distortive transition drives an improper ferroelectric polarization of 5.6 μC cm −2 along the hexagonal axis [2,6,[13][14][15]. The resulting domain structure consists of six trimerizationpolarization domain states forming vortex-like meeting points with alternating polarization around the vortex core [5,6,16].…”

Section: Introductionmentioning

confidence: 98%

Local control of improper ferroelectric domains in YMnO3

et al. 2020

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Improper ferroelectrics are described by two order parameters: a primary one, driving a transition to long-range distortive, magnetic, or otherwise nonelectric order, and the electric polarization, which is induced by the primary order parameter as a secondary, complementary effect. Using low-temperature scanning probe microscopy, we show that improper ferroelectric domains in YMnO 3 can be locally switched by electric field poling. However, subsequent temperature changes restore the as-grown domain structure as determined by the primary lattice distortion. The backswitching is explained by uncompensated bound charges occurring at the newly written domain walls due to the lack of mobile screening charges at low temperature. Thus, the polarization of improper ferroelectrics is in many ways subject to the same electrostatics as in their proper counterparts, yet complemented by additional functionalities arising from the primary order parameter. Tailoring the complex interplay between primary order parameter, polarization, and electrostatics is therefore likely to result in novel functionalities specific to improper ferroelectrics.

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Section: Introductionmentioning

confidence: 98%

Local control of improper ferroelectric domains in YMnO3

et al. 2020

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“…The multiferroic hexagonal manganites, h-RMnO 3 (R= Dy-Lu, In, Y or Sc) are improper ferroelectrics where the polarization emerges as a secondary effect due to an improper coupling to the primary distortion mode. This results in unusual ferroelectric domain structures in which topological protection of the domain wall intersections causes fundamentally and technologically interesting physical properties ranging from early universe analogues [1][2][3] to nanoscale conducting channels [4][5][6][7][8][9][10][11] . In spite of multiple studies, the evolution of the polarization with temperature has not been explained on a microscopic level.…”

Section: Introductionmentioning

confidence: 99%

Unconventional Continuous Structural Disorder at the Order-Disorder Phase Transition in the Hexagonal Manganites

et al. 2019

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The improper ferroelectricity in YMnO3 and other related multiferroic hexagonal manganites are known to cause topologically protected ferroelectric domains that give rise to rich and diverse physical phenomena. The local structure and structural coherence across the ferroelectric transition, however, were previously not well understood. Here we reveal the evolution of the local structure with temperature in YMnO3 using neutron total scattering techniques, and interpret them with the help of first-principles calculations. The results show that, at room temperature, the local and average structures are consistent with the established ferroelectric P 63cm symmetry. On heating, both local and average structural analyses show striking anomalies from ∼ 800 K up to the Curie temperature consistent with increasing fluctuations of the order parameter angle. These fluctuations result in an unusual local symmetry lowering into a continuum of structures on heating. This local symmetry breaking persists into the high-symmetry non-polar phase, constituting an unconventional type of order-disorder transition.arXiv:1707.09649v2 [cond-mat.mtrl-sci]

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