Non-Linear Dielectric Response of Ferroelectrics, Relaxors and Dipolar Glasses

Miga, S.; Dec, Jan; Kleemann, W.

doi:10.5772/20380

Cited by 12 publications

(10 citation statements)

References 61 publications

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“…In contrast, a 3 is negative both in the PE and FE phases for the discontinuous FE-PE phase transition. Additionally, a jump in the magnitude of a 3 occurs for this transition [43]. Moreover, a 3 is positive when the nonlinearity originates from the anisotropy of the polarizability.…”

Section: Introductionmentioning

confidence: 85%

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The composition induced crossover in nonlinear dielectric response in (1 − x) Pb(Zr0.70Ti0.30)O3–x BiMn2O5 (x = 0, 0.02, 0.055, 0.11, 0.15, 0.22, and 1) ceramics

2020

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Ceramics based on lead zirconate-titanate Pb(Zr 0.70 Ti 0.30)O 3 (PZT), bismuth manganite (BM) and the composite (1 − x) PZT-x BM were obtained. A systematic study of linear and nonlinear dielectric susceptibilities temperature and frequency dependences was conducted. A composition-induced crossover in nonlinear dielectric susceptibility was detected. The so-called scaled nonlinear susceptibility, a 3 , was obtained from experimental values of the real part of the linear and third-order nonlinear dielectric susceptibilities. The value for a 3 was negative for low BM content in the whole temperature range specific to discontinuous ferroelectric phase transitions and relaxor behavior. In contradiction, a 3 was positive for BM and for the composite with sufficiently high BM content. The positive a 3 was attributed to a subsystem of dipoles created by trapped charges. Hopping charge transfer, which is a dominant mechanism for conduction in manganites, is responsible for the positive a 3 and for the colossal magnitude of the imaginary part of the linear dielectric susceptibility. The concentration of the ions was determined using scanning electron microscopy. The chemical disorder and the precipitation of ions determined using time of flight-secondary ion mass spectrometry correspond to a crossover in the electrical features.

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Section: Introductionmentioning

confidence: 85%

“…Moreover, a 3 is positive when the nonlinearity originates from the anisotropy of the polarizability. In contrast, ferroelectric relaxors always exhibit a negative a 3 [43]. Therefore, a scaled nonlinear susceptibility can be applied to distinguish several types of dielectric materials.…”

Section: Introductionmentioning

confidence: 99%

The composition induced crossover in nonlinear dielectric response in (1 − x) Pb(Zr0.70Ti0.30)O3–x BiMn2O5 (x = 0, 0.02, 0.055, 0.11, 0.15, 0.22, and 1) ceramics

2020

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“…Upon cooling below 28K, negative-valued peaks in (T) ( fig. 5(d) top-left inset) evidence relaxor-like shortrange dipolar correlations, with zero net macroscopic polarization [27]. In the same regime, (T) shows a changeover from negative-to positive-valued peaks.…”

Section: Introductionmentioning

confidence: 88%

“…To characterize the dielectric state non-linear properties viz., the first-order harmonic ( ) and secondorder harmonic ( ) are good tools of study. First harmonic signal directly correlates with the polarization state of the system, expressing itself as [27];…”

Section: Introductionmentioning

confidence: 99%

“…In the free-energy density functional, B is the proportionality factor for biquadratic polarization-term (~P 2 ). First harmonic is an indirect measure of the change in local polarization (as expressed previously), and second harmonic expresses itself in terms of the polarization and fundamental dielectric susceptibility as [27]; been performed here, which significantly affects the relaxation features of the system compared to the pure PMN ceramic, the dielectric properties have been further studied under the effect of 9T magnetic field. Figure 2(b)-inset shows the dielectric constant at selected frequencies as a function of temperature under zero and 9T magnetic field.…”

Section: Introductionmentioning

confidence: 99%

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Harmonic magneto-dielectric study in doped-, double-, and layered-perovskites

Sahlot

Pandey

et al. 2020

Journal of Applied Physics

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Fundamental and harmonic magneto-dielectricity studied for varied perovskite systems--Pb 0.98 Gd 0.02 (Mg 1/3 Nb 2/3 ) 0.995 O 3 (A-site co-doped PGMN magneto-relaxor), La 0.95 Ca 0.05 CoO 3 (A-site doped spin-state LCCO), and La 2 NiMnO 6 (double-perovskite LNMO multiglass) characterize intricately polarized phases. First-harmonic signal (ε 2 ʹ) of magnetically co-doped PGMN manifests finite polarization P(H) below 270K, corroborated by the measured remnant P-E traces. Second-harmonic (ε 3 ʹ) reveals the effect of random E-fields causing electrical vitreousity, latter indicated by the divergent timescale of the fundamental response. LCCO features mixed-dipoles phase over appreciable temperature window, affiliated to the coexistent lowspins (LS) and intermediate-spins (IS). Across the 65K-start of IS-to-LS state transition (SST), dc-and acconductivities of LCCO exhibit mechanism-changeovers whereas the harmonic susceptibilities evidence IS/LS-interfacial hyper-polarizations. Below the 30K-end of SST, harmonics corroborate the vitreous phase of dipoles in the LS-matrix state. In the LNMO, positive and negative (dual) magneto-dielectricity observed is respectively attributed to the charge-hopping between Ni 2+ and Mn 4+ ions and the interfacial polarization. Second-harmonic signal here also features dispersion corresponding to the activation energy required for the electron transfer between Ni-and Mn-cations. Results from three different perovskite systems signify the combined importance of first-and second-harmonics, for a detailed understanding of electrical configurations.close to the exchange energy, stabilizing the low-spin (LS) state with configuration. HS and IS states accompany Jahn-Teller monoclinic distortions in the parent rhombohedral structure [16]. Across the IS-LS spin state transition, study of the stretching modes via Raman spectra, corresponding to different spin states, confirmed the gradual change from one spin state to another, and their coexistence over a temperature window corresponds to an order of magnitude dispersive change in the dielectric properties [16]. This vast change is traced to a mixed electrical state, comprising of phase-coexistent dipoles affiliated to the respective spin-states [17]. Thus, the system qualifies for the dielectric study of the bulk electrical-interface, as the inter-domain region between two simpler electrical mediums is well-acknowledged for device applications, because it cohosts the properties of both the media [18]. Analogous to the magneto-electricity in the composites, bulkinterfaces with no centrosymmetry in structurally single-phase materials can feature properties that are absent in the respective pure bulk media. Interestingly, La-site doping has evidenced intrinsic magnetic phase separation (magnetic glass, ferromagnetic clusters), which mandates further exploration [19]. In this regard 5% Ca-doped La 0.95 Ca 0.05 CoO 3 (LCCO) is chosen for the present study. This system has been studied in literature with signatures of SST in the dielectric properti...

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