Electron emission at switching of ferroelectrics

Rosenman, G.; Malyshkina, O. V.; Chepelev, Yu. L.

doi:10.1080/00150199008008906

Cited by 49 publications

(17 citation statements)

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“…[2][3][4][5] Current densities of Ͼ100 A/cm 2 from lead zirconate titanate (PZT) and PLZT were achieved by Riege and Gundel of CERN ‡ in 1989, 6 and, at the same time, they noted theoretical current densities of up to 10 4 -10 5 A/cm 2 . The reported emission current density varied over a range of 10 Ϫ9 -4 ϫ 10 2 A/cm 2 .…”

Section: S Ince the Discovery Of Electron Emission In Ferroelectrics Bymentioning

confidence: 99%

X‐ray Studies of Ferroelectric Cathodes

Zhang

Cai

Zhong

et al. 2000

Journal of the American Ceramic Society

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Ferroelectric electron emission has two possible sources: rapid polarization switching and surface plasma discharge. The present paper uses an X-ray diffraction (XRD) method to support the theory of rapid polarization switching for lead zirconate titanate samples. A decrease in the 002 peak value and an increase in the 200 peak value were observed after electron emission in two types of samples, which were doped with lanthanum and neodymium. A comparison of the XRD data for the samples showed that a high-density electron emission was related to a high-value polarization switch. These results were consistent with the theory of rapid polarization switching.

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Section: S Ince the Discovery Of Electron Emission In Ferroelectrics Bymentioning

confidence: 99%

X‐ray Studies of Ferroelectric Cathodes

Zhang

Cai

Zhong

et al. 2000

Journal of the American Ceramic Society

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“…For example, multielectron ferronic states in antiferromagnetic semiconductors are well known. The intensive electron emission 33,34 and luminescence [35][36][37] observed during ferroelectric switching are indicative of the existence of many electrons involved in the repolarization process. 32.…”

Section: Repolarization Nuclei As Fluctuonsmentioning

confidence: 99%

Fluctuon effects in ferroelectric polarization switching

Molotskii

Kris

Rosenman

2000

Journal of Applied Physics

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The perplexing problem of the extremely large activation energy for nucleation U ac ϳ10 6 eV, which, as was shown by Landauer, appears in the Merz thermal-fluctuational theory of ferroelectric switching, is examined. Such enormous values of U ac are a result of the combined contribution of the energy of the depolarization field and the surface energy of the nucleus. While the depolarizing field term can be reduced by a redistribution of free charges, the surface energy term alone is too large ͑greater than 10 4 eV) for thermal-fluctuation-aided nucleation to be possible. This conclusion contradicts the numerous observations of a rapid increase in the number of repolarization nuclei with temperature, which suggest that the actual activation energy is on the order of an electron volt. This article is devoted to the problem of how the surface energy of a nucleus can be compensated. It is assumed that repolarization nuclei form by a fluctuon mechanism, and it is shown how this assumption can help in resolving the conflict between theory and experiment. It is suggested that upon application of an external electric field, electrons tunnel into the region where the spontaneous polarization vector fluctuates. This fluctuation region maintains its stability owing to the field of the electrons localized within the region. This leads to the appearance of a multielectron fluctuon, which is a bound state of electrons and a fluctuation and can be regarded as a repolarization nucleus. The electronic structure of these nuclei is calculated with density-functional theory. The calculations show that fluctuon effects can fully compensate the surface energy term. The assumption that repolarization nuclei have a fluctuon nature is shown to account for the principal laws governing the switching process, including low activation energy values. The results of possible experiments that could verify the proposed mechanism are predicted.

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“…The first experimental results concerning low density (below 10 À7 A/cm 2 ) electron emission were reported for PbGe 5 O 11 [1] and TGS [2][3][4] single crystals. This low density electron emission can be attributed to the reverse of the spontaneous electric polarization and it was observed in the ferroelectric phase.…”

Section: Introductionmentioning

confidence: 98%

“…Electron emission from ferroelectrics, excited by an external electric field, is known since eighties [1][2][3][4]. The first experimental results concerning low density (below 10 À7 A/cm 2 ) electron emission were reported for PbGe 5 O 11 [1] and TGS [2][3][4] single crystals.…”

Section: Introductionmentioning

confidence: 99%