Experimental evidence for an intermediate phase in the multiferroic YMnO<sub>3</sub>

Nénert, Gwilherm; Pollet, M.; Marinel, Sylvain; Blake, Graeme R.; Meetsma, Auke; Palstra, Thomas

doi:10.1088/0953-8984/19/46/466212

Cited by 55 publications

(70 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Fennie et al [25] and Kim et al [23] supported the path of a single transition (at ∼1270 K), driven by a K 3 order parameter which couples to a secondary zone centre order parameter (associated with − 2 ) to induce ferroelectricity. In contrast to this, some studies [14,24,26] have suggested one of the paths that involves an intermediate phase between the paraelectric P6 3 /mmc phase and the ferroelectric P6 3 cm phase. The most recent powder neutron diffraction data agree with the assessment of a single, continuous high temperature phase transition causing a tripling of the unit cell at ∼1258 K from P6 3 /mmc to polar P6 3 cm [15].…”

Section: Introductionmentioning

confidence: 93%

“…Of these materials YMnO 3 , with a layered structure with Y ions placed between sheets of corner sharing MnO 5 triangular bipyramids, has been of particular interest [9][10][11][12][13][14][15][16]. It is ferroelectric (FE) below ∼900-1300 K and antiferromagnetic (AFM) below ∼75 K [15].…”

Section: Introductionmentioning

confidence: 99%

“…The temperatures of the high temperature phase transitions in hexagonal YMnO 3 have been the subject of much debate [3,14,[19][20][21][22][23]. A symmetry analysis [15,24,25] shows that there are three possible paths from the high temperature P6 3 /mmc phase to the room temperature ferroelectric P6 3 cm phase, summarized in figure 1.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Elastic anomalies associated with structural and magnetic phase transitions in single crystal hexagonal YMnO₃

Thomson

Chatterji

Howard

et al. 2014

J. Phys.: Condens. Matter

Self Cite

View full text Add to dashboard Cite

Resonant ultrasound spectroscopy has been used to measure the elastic and anelastic behaviour through known structural and magnetic phase transitions in single crystal hexagonal YMnO 3 . Anomalous elastic behaviour is observed at the high temperature structural transition at ∼1260 K, with a discontinuity in the elastic constants and nonlinear recovery below T c , consistent with λeQ 2 s coupling. There is no change in dissipation associated with this high temperature transition, and no evidence in the elastic or anelastic behaviour for any secondary transition at ∼920 K, thus supporting the thesis of a single high temperature transformation. Elastic stiffening is observed on cooling through T N , in accordance with previous studies, and the excess elastic constant appears to scale with the square of the magnetic order parameter. The strains incurred at T N are a factor of ∼20 smaller than those at the structural transition, implying very weak λeQ 2 m coupling and a dominant contribution to the variation in the elastic constants from λe 2 Q 2 m . The increased acoustic dissipation above T N is consistent with an order-disorder process.

show abstract

Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Elastic anomalies associated with structural and magnetic phase transitions in single crystal hexagonal YMnO₃

Thomson

Chatterji

Howard

et al. 2014

J. Phys.: Condens. Matter

Self Cite

View full text Add to dashboard Cite

show abstract

“…In some of these cases ferroelectricity has been claimed to emerge together with a trimerizing lattice distortion in a single-step transition 16,18,19 . In other cases these two features have been proposed to occur separately [10][11][12][13][14][15] . On the theoretical side, the two-transition scenario has initially been supported by density-functional-theory calculations 20 .…”

mentioning

confidence: 99%

Ferroelectricity in the multiferroic hexagonal manganites

et al. 2015

View full text Add to dashboard Cite

1The emergence of the spontaneous polarization in the hexagonal RMnO 3 system (R = Sc, Y, In, Dy -Lu) is one of the singular properties and, at the same time, one of the greatest mysteries of this class of compounds. Taking YMnO 3 as reference compound for the series (see Methods), Curie temperatures inexplicably spreading from 910 K to 1250 K have been reported 10-16, 18, 19 . In some of these cases ferroelectricity has been claimed to emerge together with a trimerizing lattice distortion in a single-step transition 16,18,19 . In other cases these two features have been proposed to occur separately [10][11][12][13][14][15] . On the theoretical side, the two-transition scenario has initially been supported by density-functional-theory calculations 20 . A more detailed analysis, however, suggests improper ferroelectricity triggered by the lattice trimerization in a single-step transition 21,22 , in which secondary anomalies are yet possible due to the breaking of residual symmetries 23 . Direct measurement of the spontaneous polarization as function of temperature would clarify this puzzling situation. This was done once in a pyrocurrent measurement which pointed to an onset of ferroelectricity at 933 K 16 . All attempts to reproduce this experiment failed, however. Thus, in spite of 50 years of research, the emergence of the polar order in the hexagonal RMnO 3 multiferroics is surrounded by contradictions. This uncertainty extends to the universality class of this ferroelectric transition, as this basic question depends on the precise nature of the state undergoing the polar instability. The universality class and the corresponding critical behavior determines important physical properties from the macro-to the nanoscale. Understanding such functionalities is infinitely more difficult if the emergence of the ferroelectric order itself is unclear. Thus, for putting the intense research on the unusual properties of ferroelectric order in the hexagonal RMnO 3 system 2, 3, 5,8,9 onto a solid basis, this situation must be resolved. 2Here we present nonlinear optical experiments in which the electromagnetic field of a frequency-doubled light wave couples directly and linearly to the spontaneous polarization of YMnO 3 .They reveal a polarization emerging at T C 1259 K with a subdued increase in amplitude showing no anomalies or discontinuities. Piezoresponse force microscopy (PFM) confirms that the ferroelectric domain pattern is seeded right below T C . Monte-Carlo simulations reveal how topologically created vortex-like defects in the MnO 5 tilt pattern determine the ferroelectric state and many of its unusual properties. In particular, we show that the "second transition" below T C is not associated to a phase transition, but caused by a finite-size scaling effect.At room temperature, the spontaneous polarization P s = 5.6 µC/cm 2 of YMnO 3 is observed together with unit-cell-trimerizing tilts of the MnO 5 bipyramids and Y displacements along the c axis. The tilt is parameterized 22, 23 by the observable amplitude ...

show abstract

“…After there has been some debate concerning the thermodynamic path occurring at the transition between the paraelectric P 6 3 /mmc (Z=2) and ferroelectric P 6 3 cm (Z=6) phases in YMnO 3 recent experimental and theoretical investigations agree in that the cell-tripled improper ferroelectric structure arises directly at the Curie temperature T C of about 1260 K. [1][2][3][4][5][6][7][8][9] A confirmation of this direct path is the observation of a ferroelectric domain pattern below T C consistent with the twodimensional-order-parameter symmetry associated with the K 3 zone-boundary phonon mode at k = ( 1 3 , 1 3 , 0). [10][11][12][13][14][15][16] The corresponding symmetry-breaking mechanism gives rise to a total of six domain states.…”

mentioning

confidence: 99%

Combinatorial model for the ferroelectric domain-network formation in hexagonal manganites

et al. 2014

View full text Add to dashboard Cite

As the result of the high-temperature improper ferroelectric transition occurring in YMnO3 and other hexagonal manganites a striking domain pattern was observed: an emergence of six domains of alternating polarization from one point in a vortex-like pattern. We derive the formation and distribution of the domain-vortex network from a combinatorial analysis based on order-parameter symmetry and lattice geometry. The analysis leads to stable vortex-like configurations of the six domain states in the basal plane perpendicular to the polarization and to fragmented vortices in planes parallel to the polarization. The predictions are debated in the light of existing experimental and theoretical work on the vortex domain state. The relation of the symmetry-determined geometrical defects to the topological defects proposed to describe the behavior of YMnO3 near the Curie temperature is discussed.

show abstract

Experimental evidence for an intermediate phase in the multiferroic YMnO₃

Cited by 55 publications

References 25 publications

Elastic anomalies associated with structural and magnetic phase transitions in single crystal hexagonal YMnO₃

Elastic anomalies associated with structural and magnetic phase transitions in single crystal hexagonal YMnO₃

Ferroelectricity in the multiferroic hexagonal manganites

Combinatorial model for the ferroelectric domain-network formation in hexagonal manganites

Contact Info

Product

Resources

About

Experimental evidence for an intermediate phase in the multiferroic YMnO3

Cited by 55 publications

References 25 publications

Elastic anomalies associated with structural and magnetic phase transitions in single crystal hexagonal YMnO3

Elastic anomalies associated with structural and magnetic phase transitions in single crystal hexagonal YMnO3

Ferroelectricity in the multiferroic hexagonal manganites

Combinatorial model for the ferroelectric domain-network formation in hexagonal manganites

Contact Info

Product

Resources

About

Experimental evidence for an intermediate phase in the multiferroic YMnO₃

Elastic anomalies associated with structural and magnetic phase transitions in single crystal hexagonal YMnO₃

Elastic anomalies associated with structural and magnetic phase transitions in single crystal hexagonal YMnO₃