Polarization dynamics and formation of polar nanoregions in relaxor ferroelectrics

Vugmeǐster, B. E.

doi:10.1103/physrevb.73.174117

Cited by 107 publications

(67 citation statements)

References 57 publications

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“…The length scales studied with neutrons and the expected size of the polar nanoregions have been discussed by Vugmeister. 38 In the case of the linear scans measured along ͑H , H , 2.9͒ we would expect to study polar correlations with a length scale ϳ 1/q ϳ 6 Å, which is a very short length scale compared to other techniques. It therefore is possible that the time dependence measured with birefringence is associated with longer length scales than investigated here.…”

Section: B Diffuse Scattering Near Q ᠬ = "003…mentioning

confidence: 99%

Neutron and x-ray diffraction study of cubic [111] field-cooledPb(Mg1∕3Nb2∕3)
Stock
¹
,
Xu
²
,
Gehring
³

et al. 2007
Phys. Rev. B
60
3
46
2
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Neutron and x-ray diffraction techniques have been used to study the competing long-and short-range polar order in the relaxor ferroelectric Pb͑Mg 1/3 Nb 2/3 ͒O 3 ͑PMN͒ under a ͓111͔ applied electric field. Despite reports of a structural transition from a cubic phase to a rhombohedral phase for fields E Ͼ 1.7 kV/ cm, we find that the bulk unit cell remains cubic ͑within a sensitivity of 90°−␣ = 0.03°͒ for fields up to 8 kV/ cm. Furthermore, we observe a structural transition confined to the near surface volume or "skin" of the crystal where the cubic cell is transformed to a rhombohedral unit cell at T c = 210 K for E Ͼ 4 kV/ cm, for which 90°−␣ = 0.08± 0.03°b elow 50 K. While the bulk unit cell remains cubic, a suppression of the diffuse scattering and concomitant enhancement of the Bragg peak intensity is observed below T c = 210 K, indicating a more ordered structure with increasing electric field yet an absence of a long-range ferroelectric ground state in the bulk. The electric field strength has little effect on the diffuse scattering above T c , however, below T c the diffuse scattering is reduced in intensity and adopts an asymmetric line shape in reciprocal space. The absence of hysteresis in our neutron measurements ͑on the bulk͒ and the presence of two distinct temperature scales suggests that the ground state of PMN is not a frozen glassy phase as suggested by some theories but is better understood in terms of random fields introduced through the presence of structural disorder. Based on these results, we also suggest that PMN represents an extreme example of the two-length scale problem, and that the presence of a distinct skin may be necessary for a relaxor ground state.

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Section: B Diffuse Scattering Near Q ᠬ = "003…mentioning

confidence: 99%

Neutron and x-ray diffraction study of cubic [111] field-cooledPb(Mg1∕3Nb2∕3)
Stock
¹
,
Xu
²
,
Gehring
³

et al. 2007
Phys. Rev. B
60
3
46
2
View full text Add to dashboard Cite

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“…Although this was originally an empirical model extending Arrhenius-type relaxations, it has been retroactively derived theoretically from different assumptions. Two recent and different post facto derivations are given in [16,17]. In the literature such VogelFulcher fits to relaxor data (such as PMN) generally give finite freezing temperatures T f .…”

Section: The Search For New Quantum Critical Point (Qcp) Ferroelecmentioning

confidence: 99%

Quantum critical points in ferroelectric relaxors: Stuffed tungsten bronze K3Li2Ta5O
Smith
¹
,
Gardner
²
,
Morrison
³

et al. 2018
Phys. Rev. Materials
3
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2
0
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We have synthesized ceramic specimens of the tetragonal tungsten bronze K 3 Li 2 Ta 5 O 15 (KLT) and characterized its phase transition via x-ray diffraction, dielectric permittivity, resonant ultrasonic spectroscopy, and heat capacity measurements. The space group of KLT is reported as both P 4/mbm and Cmmm with the orthorhombic distortion occurring when there are higher partial pressures of volatile K and Li used inside the closed crucibles for the solid state synthesis. The data show strong relaxor behavior, with the temperature at which the two dielectric relative permittivity peaks decreasing, with 104 T m1 69 K and 69 T m2 46 K as probe frequency f is reduced from 1 MHz to 316 Hz. F tests show that the data satisfies a Vogel-Fulcher model better than Arrhenius with an extrapolated freezing temperature for ε and ε of T f 1 = +15.8 and −11.8 K and T f 2 = −5.0 and −15.0 K for f → 0 (tending to dc). This difference between T f from real and imaginary values, albeit counterintuitive, is mandatory, according to the theory of Tagantsev. Therefore, by tuning frequency, the transition could be shifted to absolute zero, suggesting KLT has a relaxor-type quantum critical point. In addition, we have reanalyzed the conflicting literature for Pb 2 Nb 2 O 7 pyrochlore which suggests that this also has a relaxor-type quantum critical point since the freezing temperature from the Vogel-Fulcher fitting is below absolute zero. Since the transition temperature evidenced in the dielectric data at approximately 100 kHz shifts below 0 K for very low frequencies, this transition would not be seen with heat capacity data collected in the zero-frequency (dc) limit. Both of these materials show promise for possible new relaxor-type quantum critical points with nonperovskite based structures. DOI: 10.1103/PhysRevMaterials.2.084409 I. THE SEARCH FOR NEW QUANTUM CRITICAL POINT (QCP) FERROELECTRICS INCLUDING RELAXOR QCPSQuantum critical point (QCP) studies of ferroelectrics have been limited to a few crystal structures, emphasizing perovskite oxides. The drive to find new QCPs with ferroelectrics (FEs) are of interest due to the likelihood that they will exhibit novel electrical and thermal properties over wide ranges in temperature and tuning parameters, similar to what is seen in more widely studied magnetic counterparts. However, as the dynamical exponent is 1 for displacive FE rather than 3 for itinerant ferromagnets, the understanding and modeling of their properties are likely to be more complex, since real systems can exceed the upper and lower critical dimensionality [1]. For a QCP to occur, the transition should be driven by quantum fluctuations rather than classical fluctuations, and such quantum fluctuations tend to dominate in a region just above 0 K. Interest in ferroelectric quantum critical points has grown rapidly in the past several years, with emphasis upon perovskites [1,2] and several other materials, including hexaferrites [3][4][5][6] and organic or molecular crystals [7][8][9][10]. However, the QCPs studied thus ...

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“…While this is appropriate in cases where thermodynamics of the switching process is the only determining factor, there exist a wide range of phenomena ranging from ionic redistribution [118,128] in mixed ionic/electronic conductors to polarization dynamics in relaxor ferroelectrics, [129] which exhibit strong time-dependent properties. Recently, Kumar et al [117] demonstrated a technique, termed as dynamic switching spectroscopy PFM (D-SSPFM) in which the thermodynamic and kinetic effects in local bias measurements can be separated.…”

Section: E 5d Spectroscopy: Dynamic Pfmmentioning

confidence: 99%

Spectroscopic imaging in piezoresponse force microscopy: New opportunities for studying polarization dynamics in ferroelectrics and multiferroics

et al. 2012

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Piezoresponse force microscopy (PFM) has emerged as a powerful tool to characterize piezoelectric, ferroelectric, and multiferroic materials on the nanometer level. Much of the driving force for the broad adoption of PFM has been the intense research into piezoelectric properties of thin films, nanoparticles, and nanowires of materials as dissimilar as perovskites, nitrides, and polymers. Recent recognition of limitations of single-frequency PFM, notably topography-related cross-talk, has led to development of novel solutions such band-excitation (BE) methods. In parallel, the need for quantitative probing of polarization dynamics has led to emergence of complex time-and voltage spectroscopies, often based on acquisition and analysis of multidimensional datasets. In this perspective, we discuss the recent developments in multidimensional PFM, and offer several examples of spectroscopic techniques that provide new insight into polarization dynamics in ferroelectrics and multiferroics. We further discuss potential extension of PFM for probing ionic phenomena in energy generation and storage materials and devices.

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Polarization dynamics and formation of polar nanoregions in relaxor ferroelectrics

Cited by 107 publications

References 57 publications

Neutron and x-ray diffraction study of cubic [111] field-cooledPb(Mg1∕3Nb2∕3)
Stock
¹
,
Xu
²
,
Gehring
³

et al. 2007
Phys. Rev. B
60
3
46
2
View full text Add to dashboard Cite

Neutron and x-ray diffraction study of cubic [111] field-cooledPb(Mg1∕3Nb2∕3)
Stock
¹
,
Xu
²
,
Gehring
³

et al. 2007
Phys. Rev. B
60
3
46
2
View full text Add to dashboard Cite

Quantum critical points in ferroelectric relaxors: Stuffed tungsten bronze K3Li2Ta5O
Smith
¹
,
Gardner
²
,
Morrison
³

et al. 2018
Phys. Rev. Materials
3
0
2
0
View full text Add to dashboard Cite

Spectroscopic imaging in piezoresponse force microscopy: New opportunities for studying polarization dynamics in ferroelectrics and multiferroics

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Polarization dynamics and formation of polar nanoregions in relaxor ferroelectrics

Cited by 107 publications

References 57 publications

Neutron and x-ray diffraction study of cubic [111] field-cooledPb(Mg1∕3Nb2∕3)Stock1, Xu2, Gehring3 et al. 2007Phys. Rev. B603462View full textAdd to dashboardCite

Neutron and x-ray diffraction study of cubic [111] field-cooledPb(Mg1∕3Nb2∕3)Stock1, Xu2, Gehring3 et al. 2007Phys. Rev. B603462View full textAdd to dashboardCite

Quantum critical points in ferroelectric relaxors: Stuffed tungsten bronze K3Li2Ta5OSmith1, Gardner2, Morrison3 et al. 2018Phys. Rev. Materials3020View full textAdd to dashboardCite

Spectroscopic imaging in piezoresponse force microscopy: New opportunities for studying polarization dynamics in ferroelectrics and multiferroics

Contact Info

Product

Resources

About

Neutron and x-ray diffraction study of cubic [111] field-cooledPb(Mg1∕3Nb2∕3)
Stock
¹
,
Xu
²
,
Gehring
³

et al. 2007
Phys. Rev. B
60
3
46
2
View full text Add to dashboard Cite

Neutron and x-ray diffraction study of cubic [111] field-cooledPb(Mg1∕3Nb2∕3)
Stock
¹
,
Xu
²
,
Gehring
³

et al. 2007
Phys. Rev. B
60
3
46
2
View full text Add to dashboard Cite

Quantum critical points in ferroelectric relaxors: Stuffed tungsten bronze K3Li2Ta5O
Smith
¹
,
Gardner
²
,
Morrison
³

et al. 2018
Phys. Rev. Materials
3
0
2
0
View full text Add to dashboard Cite