Manganese-doping enhanced local heterogeneity and piezoelectric properties in potassium tantalate niobate single crystals

Ion doping, an effective way to modify the nature of materials, is beneficial for the improvement of material properties. Mn doping exhibits gain of piezoelectric properties in KTa1−x Nb x O3 (KTN). However, the impact mechanism of Mn ions on properties remains unclear. Here, the effects of Mn doping on local heterogeneity and piezoelectric properties in KTN are studied. The electric field-induced strain of Mn-doped KTN is ∼0.25% at 10 kV cm−1, 118% higher than that of pristine KTN. Meanwhile, as a result of Mn doping, the dielectric permittivity was tripled and the ferroelectricity was modified. The changes in A1(2TO), B1 + E(3TO) and E(4TO) vibrations characterized by Raman spectra indicate increased local polarization, weak correlation of dipoles and distorted lattices in Mn-doped KTN, respectively. First-principles calculations demonstrate stronger local heterogeneity introduced by Mn dopants, which weakens the dipole correlations and reduces domain sizes. As a result, the decreased domain sizes, combined with the larger ratio of lattice parameters c and a of the Mn-contained portion, are responsible for the higher piezoelectricity. This work reveals the impact on properties of KTN from Mn dopants and the prominent role of local heterogeneity in improving piezoelectricity, being valuable for the optimization and design of material properties.

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Influence of Insulating Material Properties on Partial Discharges at DC Voltage

Energies ◽

10.3390/en13174305 ◽

2020 ◽

Vol 13 (17) ◽

pp. 4305

Author(s):

Marek Florkowski

Keyword(s):

Material Properties ◽

Dielectric Material ◽

Partial Discharge ◽

Partial Discharges ◽

Time Interval ◽

Post Discharge ◽

Insulating Material ◽

Dc Voltage ◽

The Impact

Understanding a partial discharge mechanism at direct current (DC) is an actual research topic that requires both modeling, simulations and measurements. This paper describes an influence of insulating material properties on partial discharges at DC voltage. Modifications of the traditional model reflecting the conditions of partial discharges (PD) inception and post discharge processes at DC voltage have been proposed. The aim was to show the partial discharge mechanisms and draw attention to the role of parameters of insulation materials adjacent to the cavity at DC voltage. The investigations were performed on two kinds of dielectric material used in power cables. Various combinations of specimens were designed to reveal the effect of the material resistivity on the PD activity. Key observations referred to the impact of the void adjacent material resistance on the partial discharge inception voltage threshold at DC voltage. The modified PD model was applied to analyze both inception and post discharge recovery stage. The role of dielectric properties of material adjacent to the void was investigated, highlighting its impact during static inception stage and in charging stage. Despite many simplifications introduced in the model, measurement results have confirmed the role of the dielectric material surrounding the void on partial discharge dynamics. The average time interval between PD pulses revealed a systematic relationship with respect to the applied voltage and specimen resistivity. This value can be considered in the future research for diagnostic indicator at DC voltage.

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Defect engineering of BCZT-based piezoelectric ceramics with high piezoelectric properties

Journal of Advanced Ceramics ◽

10.1007/s40145-021-0526-6 ◽

2021 ◽

Vol 11 (1) ◽

pp. 184-195

Author(s):

Xinjian Wang ◽

Yu Huan ◽

Yixuan Zhu ◽

Peng Zhang ◽

Wenlong Yang ◽

...

Keyword(s):

Oxygen Partial Pressure ◽

Partial Pressure ◽

Conduction Mechanism ◽

Piezoelectric Properties ◽

Hole Concentration ◽

Doping Element ◽

Mn Doping ◽

Mechanical Coupling ◽

Intrinsic Conduction ◽

Mn Doped

AbstractThe intrinsic conduction mechanism and optimal sintering atmosphere of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT) ceramics were regulated by Mn-doping element in this work. By Hall and impedance analysis, the undoped BCZT ceramics exhibit a typical n-type conduction mechanism, and the electron concentration decreases with the increasing oxygen partial pressure. Therefore, the undoped ceramics exhibit best electrical properties (piezoelectrical constant d33 = 585 pC·N−1, electro-mechanical coupling factor kp = 56%) in O2. A handful of Mn-doping element would transfer the conduction mechanism from n-type into p-type. And the hole concentration reduces with the decreasing oxygen partial pressure for Mn-doped BCZT ceramics. Therefore, the Mn-doped ceramics sintered in N2 have the highest insulation resistance and best piezoelectric properties (d33 = 505 pC·N−1, kp = 50%). The experimental results demonstrate that the Mn-doping element can effectively adjust the intrinsic conduction mechanism and then predict the optimal atmosphere.

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Dense Manganese Doped Biphasic Calcium Phosphate for Load Bearing Bone Implants

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.93-94.393 ◽

2010 ◽

Vol 93-94 ◽

pp. 393-396 ◽

Cited By ~ 3

Author(s):

Iis Sopyan ◽

Natasha Ahmad Nawawi ◽

Qasim Hussain Shah

Keyword(s):

Calcium Phosphate ◽

Biphasic Calcium Phosphate ◽

Sintering Temperature ◽

Sol Gel ◽

Maximum Hardness ◽

Mn Doping ◽

Manganese Doping ◽

Air Atmosphere ◽

Tcp Phases ◽

Mn Doped

Dense pure biphasic calcium phosphate (BCP) and Mn-doped BCP ceramics were fabricated via uniaxial pressing using the sol-gel derived powders. The compacted discs were sintered in air atmosphere with temperatures ranging from 1000 °C to 1400 °C. All powders have been proved to show HA and β-TCP phases only. Manganese doping improves the densification in the BCP structure as the relative density increased with Mn doping and also sintering temperature. Considerable grain growth has been observed at 1300 °C for Mn-doped BCP samples compared to the pure BCP. 15 mol% Mn showed the maximum hardness value of 6.66 GPa at 1400 °C compared to pure BCP of only 2.89 GPa. Similarly, the Mn-doped BCP has superior fracture toughness where it attained maximum values of 1.05 MPam1/2 at 1400 °C compared to 0.72 MPam1/2 at 1300 °C of pure BCP. In a nutshell, Mn doping has successfully brought improvement in the mechanical properties of the BCP.

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Role of Material Properties in the Finite Element Solution for Three-Dimensional Composites—A Sensitivity Study

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1243/pime_proc_1995_209_282_02 ◽

1995 ◽

Vol 209 (2) ◽

pp. 157-160

Author(s):

H-B Hellweg ◽

M A Crisfield

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Material Properties ◽

Three Dimensional ◽

Transversely Isotropic ◽

Sensitivity Study ◽

Two Dimensional ◽

Element Analysis ◽

The Impact

Three-dimensional material test data for orthotropic laminae are difficult to obtain. Consequently, various simplifications are made for the material properties of individual layers in a finite element analysis, ranging from the assumption of transversely isotropic layers to applying two-dimensional material data in a three-dimensional analysis. In order to investigate the impact and validity of such simplifications, the sensitivity of the stresses and deformations in a finite element analysis on the material properties was investigated.

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Intergroup Threat and Outgroup Attitudes

Social Psychology ◽

10.1027/1864-9335/a000127 ◽

2013 ◽

Vol 44 (5) ◽

pp. 311-319 ◽

Cited By ~ 12

Author(s):

Marco Brambilla ◽

David A. Butz

Keyword(s):

Gay Men ◽

Social Group ◽

Welfare Recipients ◽

Intergroup Attitudes ◽

Social Policies ◽

Intergroup Threat ◽

Economic Threat ◽

The Impact ◽

General Climate

Two studies examined the impact of macrolevel symbolic threat on intergroup attitudes. In Study 1 (N = 71), participants exposed to a macrosymbolic threat (vs. nonsymbolic threat and neutral topic) reported less support toward social policies concerning gay men, an outgroup whose stereotypes implies a threat to values, but not toward welfare recipients, a social group whose stereotypes do not imply a threat to values. Study 2 (N = 78) showed that, whereas macrolevel symbolic threat led to less favorable attitudes toward gay men, macroeconomic threat led to less favorable attitudes toward Asians, an outgroup whose stereotypes imply an economic threat. These findings are discussed in terms of their implications for understanding the role of a general climate of threat in shaping intergroup attitudes.

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