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  • AIP Publishing  (5)
  • Lookman, Turab  (5)
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  • AIP Publishing  (5)
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  • 1
    In: Applied Physics Letters, AIP Publishing, Vol. 122, No. 2 ( 2023-01-09)
    Abstract: A ferroelectric phase transition under an external bias electric field after field cooling and zero field cooling in barium titanate single crystals shows scale invariant nucleation and growth of complex domain structures. The avalanche energy exponents vary with the external bias, depending on the cooling history of the sample under applied field or zero field cooling. After field cooling, resulting in a single domain sample, the energy exponent is near the integrated mean field value of 5/3, namely, 1.68 ± 0.022. The sample after field cooling shows the same exponent with an external bias electric field range of up to 4.5 kV/cm. The exponent of a multi-domain sample, after zero field cooling, decreases from ε = 1.85 to the fixed point of 1.66 under high fields. The different behavior is attributed to the greater complexity of domain patterns in the multi-domain sample, which reduces to a single domain state under strong applied fields. Compared with the single-domain state, the multi-domain state has more domain boundaries and the intersections formed by these domain boundaries. These domain boundaries and their intersections will hinder the movement of the phase boundary and act as a pinning effect on the front of the phase interface. The effect is to generate more small energy signals, making the critical exponent high. At the same time, the aftershock time distribution (Omori law) remains the same for all switching conditions with an Omori exponent near −1 and switching time correlations of −1 ± 0.05 for short times ( & lt;1 s) and −2 ± 0.10 for long times ( & gt;1 s).
    Type of Medium: Online Resource
    ISSN: 0003-6951 , 1077-3118
    RVK:
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2023
    detail.hit.zdb_id: 211245-0
    detail.hit.zdb_id: 1469436-0
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  • 2
    In: Applied Physics Letters, AIP Publishing, Vol. 111, No. 3 ( 2017-07-17)
    Abstract: An important aspect of searching for alternatives to the current piezoelectric workhorse PZT (PbZrxTi1−xO3) is to establish a vertical morphotropic phase boundary (MPB) in the composition-temperature phase diagram. However, the MPBs in most lead-free piezoelectrics, especially the BaTiO3-based piezoelectrics, are not as vertical as that of PZT, resulting in serious temperature dependence of piezoelectric and dielectric properties. We investigate the dependence of the verticality of the MPB on polarization and strain related design descriptors in BaTiO3-based and Pb-based systems. We find that the slope of the MPB decreases monotonically with the unit cell volume ratio of the tetragonal (T) and rhombohedral (R) ends; however, it increases with the ionic displacement ratio of the two ends. As the above two descriptors are not straight forward to access as a priori information, two parameters that relate to the atomic size and effective nuclear charge are introduced to enable an effective search for a desired MPB slope. Our study thus provides potential selection rules for developing Pb-free piezoelectrics with high temperature reliability.
    Type of Medium: Online Resource
    ISSN: 0003-6951 , 1077-3118
    RVK:
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2017
    detail.hit.zdb_id: 211245-0
    detail.hit.zdb_id: 1469436-0
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  • 3
    Online Resource
    Online Resource
    AIP Publishing ; 2020
    In:  Journal of Applied Physics Vol. 128, No. 1 ( 2020-07-07)
    In: Journal of Applied Physics, AIP Publishing, Vol. 128, No. 1 ( 2020-07-07)
    Abstract: An active learning strategy using sampling based on uncertainties shows the promise of accelerating the development of new materials. We study the efficiencies of the active learning iteration loop with different uncertainty estimators to find the “best” material in four different experimental datasets. We use a bootstrap approach aggregating with support vector regression as the base learner to obtain uncertainties associated with model predictions. If the bootstrap replicate number B is small, the variance estimated by the empirical standard error estimator is found to be close to the true variance, whereas the jackknife based estimators give an upward or downward biased estimation of variance. As B increases, the bias of the jackknife based estimators decreases and the variance estimated finally converges to the true one. Therefore, the empirical standard error estimator needs the least number of iteration loops to find the best material in the datasets, especially when the bootstrap replicate number B is small. Our work demonstrates that an appropriate Bootstrap replicate B is conducive to minimizing calculation costs during the materials property optimization by active learning.
    Type of Medium: Online Resource
    ISSN: 0021-8979 , 1089-7550
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2020
    detail.hit.zdb_id: 220641-9
    detail.hit.zdb_id: 3112-4
    detail.hit.zdb_id: 1476463-5
    Location Call Number Limitation Availability
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  • 4
    In: Journal of Applied Physics, AIP Publishing, Vol. 132, No. 22 ( 2022-12-14)
    Abstract: The avalanche dynamics of ferroelectric switching in lead zirconate titanate ceramics was investigated using acoustic emission. Two distinct power-law regimes for ferroelectric switching events were identified by an anomaly in the histogram of probability density, in contrast to the single power-law behavior observed in BaTiO3 single crystals. Such an anomaly is ascribed to the different minimum cut-offs of two power-law distributions. The critical energy exponents were determined to be 1.25 ± 0.10 for energies & lt;103 aJ and 1.51 ± 0.14 for energies & gt;103 aJ. The events in both regimes can be attributed to the depinning of domain walls from two distinct types of defects. The events in the lower energy regime are associated with domain wall junctions due to long-range electric and elastic interactions, whereas the latter is related to extrinsic defects, such as vacancies and dislocations. Moreover, for both regions, the rate of aftershocks follows the Omori power-law, indicating the same critical temporal correlations between the avalanches.
    Type of Medium: Online Resource
    ISSN: 0021-8979 , 1089-7550
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2022
    detail.hit.zdb_id: 220641-9
    detail.hit.zdb_id: 3112-4
    detail.hit.zdb_id: 1476463-5
    Location Call Number Limitation Availability
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  • 5
    In: Journal of Applied Physics, AIP Publishing, Vol. 117, No. 12 ( 2015-03-28), p. 124107-
    Type of Medium: Online Resource
    ISSN: 0021-8979 , 1089-7550
    Language: English
    Publisher: AIP Publishing
    Publication Date: 2015
    detail.hit.zdb_id: 220641-9
    detail.hit.zdb_id: 3112-4
    detail.hit.zdb_id: 1476463-5
    Location Call Number Limitation Availability
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