Dipole glass and ferroelectricity in random-site electric dipole systems

Vugmeǐster, B. E.; Glinchuk, M. D.

doi:10.1103/revmodphys.62.993

Cited by 635 publications

(409 citation statements)

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“…These materials exhibit very low strain-electric field hysteresis, extremely large dielectric constants, and record-setting piezoelectric coefficients at room temperature that form an unusually appealing set of properties with the potential to revolutionize a myriad of important technological applications spanning medical diagnostic sonography, military sonar, energy harvesting, and high-precision actuators (6)(7)(8). Many researchers have argued that quenched random electric fields (REFs) play a central role in establishing the relaxor phase, in part because the B sites of all known leadoxide perovskite relaxors are occupied by random mixtures of heterovalent cations (9)(10)(11)(12)(13). However, there is ample theoretical work that suggests relaxor behavior can occur in the absence of REFs (14)(15)(16).…”

mentioning

confidence: 99%

Role of random electric fields in relaxors

Phelan

Stock

Rodríguez-Rivera

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

135

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PbZr 1-x Ti x O 3 (PZT) and Pb(Mg 1/3 Nb 2/3 ) 1-x Ti x O 3 (PMN-xPT) are complex lead-oxide perovskites that display exceptional piezoelectric properties for pseudorhombohedral compositions near a tetragonal phase boundary. In PZT these compositions are ferroelectrics, but in PMN-xPT they are relaxors because the dielectric permittivity is frequency dependent and exhibits non-Arrhenius behavior. We show that the nanoscale structure unique to PMN-xPT and other lead-oxide perovskite relaxors is absent in PZT and correlates with a greater than 100% enhancement of the longitudinal piezoelectric coefficient in PMN-xPT relative to that in PZT. By comparing dielectric, structural, lattice dynamical, and piezoelectric measurements on PZT and PMN-xPT, two nearly identical compounds that represent weak and strong random electric field limits, we show that quenched (static) random fields establish the relaxor phase and identify the order parameter.lead zirconate titanate | piezoelectricity | short-range order | soft modes | neutron scattering T he remarkable electromechanical properties of lead-oxide perovskite (ABO 3 ) relaxors such as Pb(Mg 1/3 Nb 2/3 ) 1-x Ti x O 3 (PMN-xPT) and Pb(Zn 1/3 Nb 2/3 ) 1-x Ti x O 3 (PZN-xPT) have inspired numerous attempts to understand the piezoelectricity in terms of the structural phase diagram, which contains a steep morphotropic phase boundary (MPB) separating pseudorhombohedral and tetragonal states over a narrow compositional range where the piezoelectricity is maximal (1-5). These materials exhibit very low strain-electric field hysteresis, extremely large dielectric constants, and record-setting piezoelectric coefficients at room temperature that form an unusually appealing set of properties with the potential to revolutionize a myriad of important technological applications spanning medical diagnostic sonography, military sonar, energy harvesting, and high-precision actuators (6-8). Many researchers have argued that quenched random electric fields (REFs) play a central role in establishing the relaxor phase, in part because the B sites of all known leadoxide perovskite relaxors are occupied by random mixtures of heterovalent cations (9-13). However, there is ample theoretical work that suggests relaxor behavior can occur in the absence of REFs (14-16). In fact it has not been proven conclusively that REFs are essential to the relaxor state or that they play any role in the ultrahigh piezoelectricity. These basic questions persist in the face of decades of research mainly because there exists no rigorous definition of what a relaxor is, i.e., there is no precise mathematical formulation of the relaxor-order parameter. To date, any material for which the real part of the dielectric permittivity e′ðω; TÞ exhibits a broad peak at a temperature T max that depends strongly (and in some cases only weakly) on the measuring frequency, ω, is classified as a relaxor. This definition has been applied equally to PMN and PZN, which possess strong REFs, as well as to specific compositions of K(T...

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mentioning

confidence: 99%

Role of random electric fields in relaxors

Phelan

Stock

Rodríguez-Rivera

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

135

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“…These results indicate that the magnitude of P is very sensitive to both cooling E and H, that is, ME-field-cooling condition. The observed remarkable cooling H and E effects on P are reminiscent of the cooling H effect on M in spin glasses 16 and/or the cooling E effect on P in dipole glasses 17 .…”

Section: Resultsmentioning

confidence: 87%

Magnetoelectric control of frozen state in a toroidal glass

Yamaguchi

Kimura

2013

Nat Commun

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The glass state of matter represents a frozen state of an atomically disordered system with local order only. Instead of atoms, systems with glassy states of magnetic and electric dipole moments in solids are known as spin and dipole glasses, respectively. In these conventional glasses, slow dynamics, such as relaxation and memory phenomena, are characteristics of their magnetic/dielectric properties. Here we propose a new glassy state in solids, a 'toroidal glass', in which toroidal moments-vector-like electromagnetic multipole moments breaking both space inversion and time reversal symmetries, and producing a linear magnetoelectric coupling-are randomly oriented and frozen. We investigate the dynamics of a linear magnetoelectric effect in Ni 0.4 Mn 0.6 TiO 3 and find that the magnetoelectric responses strongly depend on the magnetoelectric cooling history and show striking memory effects. These unusual magnetoelectric dynamical features can be explained in the framework of a toroidal glass in which the toroidal frozen state can be controlled magnetoelectrically.

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“…Regarding the fitting of the Vogel-Fulcher relation to the high-T experimental data in KLT ceramics with x = 0.05 and 0.10, the relaxation parameters obtained evidence the apparent off-centre displacements of small lithium ions on the large potassium sites within polar clusters. 7 Moreover, the similarity of the activation energy for relaxations A2 and B1 as well as A1 and B2 implies the same type of the Li reorientations. The difference is just that Li ions flipping is individual for low-T A relaxations, while it is collective for high-T B relaxations, which then become frozen on cooling down.…”

Section: B Analysis Of the Dielectric Relaxations Of K 1-x LI X Tio mentioning

confidence: 99%

“…The combination of Li-dipoles relaxations, their interactions, and the soft mode leads to complex nature of the dielectric response in KLT. 7,8 Dielectric measurements on KLT single crystals with 0<x<0.02 reveal only one relaxational peak in (T) at low temperature, while for x>0.02, two peaks are observed. These two peaks have been associated with two distinct relaxational processes, termed low-T and high-T relaxations.…”

Section: Introductionmentioning

confidence: 99%

Lithium-induced dielectric relaxations in potassium tantalate ceramics

Tkach¹,

Almeida²,

Moreira³

et al. 2011

J. Phys. D: Appl. Phys.

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To cite this version:A Tkach, A Almeida, J Agostinho Moreira, A Espinha, M R Chaves, et al.. Lithium-induced dielectric relaxations in potassium tantalate ceramics. Journal of Physics D: Applied Physics, IOP Publishing, 2011, 44 (31) ceramics with x = 0, 0.02, 0.05, and 0.10 by measuring both the dielectric permittivity from 10 2 to 10 8 Hz, and polarization under an a.c. electric field driven at 2.5 Hz, for temperatures from 10 to 300 K. The dielectric permittivity exhibits all the relaxations reported for K1-xLixTaO3 single crystals. Two dielectric relaxations observed at 40-125 K are ascribed to the individual hopping by 90 and 180° of dipoles created by the off-centre Li ions. Another relaxation observed at 100-200 K is related to 180°-flips of Li pairs for x = 0.02 and of polar clusters of interacting Li ions for x = 0.05 and 0.10. Besides that, an additional relaxation not reported before is presented at 135-235 K for x = 0.10 and attributed to 90°-reorientation of Li polar clusters. Both the change from an Arrhenius to a Vogel-Fulcher dependence with increasing lithium content, and the emergence of slim P (E) hysteresis loops around the relaxation temperatures show that the relaxation dynamics in K1-xLixTaO3 can be understood if a crossover from a dipolar glass to a relaxor-like behavior is assumed.Keywords: Quantum paraelectricity, Lithium doped potassium tantalate, Dielectric relaxtion properties, Microscopic mechanisms AbstractThis work reports the effect of lithium doping on the dielectric and polar properties of potassium Both the change from an Arrhenius to a Vogel-Fulcher dependence with increasing lithium content, and the emergence of slim P (E) hysteresis loops around the relaxation temperatures show that the relaxation dynamics in K 1-x Li x TaO 3 can be understood if a crossover from a dipolar glass to a relaxorlike behavior is assumed.

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Dipole glass and ferroelectricity in random-site electric dipole systems

Cited by 635 publications

References 126 publications

Role of random electric fields in relaxors

Role of random electric fields in relaxors

Magnetoelectric control of frozen state in a toroidal glass

Lithium-induced dielectric relaxations in potassium tantalate ceramics

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