Lanthanum influence on the structure, dielectric properties and luminescence of BaTiO 3 ceramics processed by spark plasma sintering technique

Stanciu, Catalina-Andreea; Cernea, Marin; Secu, Elisabeta Corina; Aldica, G.; Ganea, Paul; Trușcă, Roxana

doi:10.1016/j.jallcom.2017.02.258

Cited by 29 publications

(9 citation statements)

References 25 publications

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“…The heat generated all through the SPS process is centralized on the materials particle surfaces. However, , 0 (2018) MATEC Web of Conferences https://doi.org/10.1051/matecconf/201824 249 0 0 10 9010 ICMMM 2018 4 4 due to high speed at which SPS attains completion of its process coupled with the fact that the surface temperature of the particles rises rapidly, grain growth are limited [3,7,8]. Adequate control of SPS parameters helps to ensure highly dense sintered products and also the ability to prevent little or no grain growth.…”

Section: Figure 1: Schematic Diagram Showing Sps Working Processmentioning

confidence: 99%

Comparative study of spark plasma sintering features on the densification of Ni-Cr binary alloys

et al. 2018

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Spark plasma sintering (SPS) has been widely regarded as an advanced powder consolidation technique which helps in the development of array of engineering materials. Many have been reported in the literature about sintering parameters such as temperature, pressure, heating rate and holding time. However, little or no reports has been made on some of the intricate features such as process time(s), power SPS (KW), pressing speed (mm/min), and average pressing force (KN) on which sintering parameters are directly related to. This study aims to investigate the behaviour of spark plasma sintered Ni-17Cr binary alloys with emphasis on the densification, hardness value and spark plasma sintering features such as process time (s), power SPS (KW), pressing speed (mm/min), and the average pressing force (KN). Nickel and chromium powders were milled individually using High energy ball milling for durations of 5hr, 10 hr prior to mixing and subsequent sintering. The sintered 5 hr and 10 hr milled Ni-17Cr binary alloys attained relative densities of 98.72 % and 99.1 % respectively. The Microstructural morphology was examined using Scanning electron microscopy (SEM). The sintered 10 hr milled Ni-17Cr binary alloy revealed the higher hardness.

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Section: Figure 1: Schematic Diagram Showing Sps Working Processmentioning

confidence: 99%

Comparative study of spark plasma sintering features on the densification of Ni-Cr binary alloys

et al. 2018

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“…The rhombohedral-orthorhombic phase transition (T R-O ) and orthorhombic-tetragonal phase transition (T O-T ) temperatures of all the samples can be easily marked except for BT-(K, Gd)T and BT-(K, Sm)T, where their T R-O and T O-T approach each other to form a diffused phase transition. It was previously thought that the addition of most individual rare-earth dopants can decrease T C [18,19,21] of BaTiO 3 systems except for few elements. Besides, the T O-T of other BT-(K, N)T samples moves forward to low temperatures by doping different N. Meanwhile, a remarkable feature is that the T C increased up to 145 and 139 °C for BT-(K, Ho)T and BT-(K, Y) T, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…[13] Furthermore, electrostriction is a four-rank tensor property, and thus it can be observed in all crystal symmetries. [9,11,12] On the other hand, some efforts have been employed to not only improve the electrical properties but also increase the T C of BT-based ceramics by chemical modifications, [16,17] and unfortunately most of the additives deteriorated the T C of BT-based ceramics, such as La, Gd, Sr doping in A-site [18][19][20] or Zr, Sn, Hf doping in B-site. [15] Recently, some lead-free piezoelectric ceramics with relaxor behavior have exhibited the enhancement of electrostrictive effect due to their hysteresisfree characteristics.…”

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Giant Electrostrictive Responses and Temperature Insensitive Strain in Barium Titanate‐Based Ceramics

Huang

Zhao

2018

Adv Elect Materials

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property with excellent temperature stability and improved T C in consideration of actual applications. In addition, the electrostrictive effect, serving as a basic electromechanical phenomenon in all insulators or dielectrics, has become a hot topic in the field of lead-free piezoelectric materials. [9][10][11][12] Compared with the piezoelectric effect, the electrostrictive effect has several unique advantages, including little or no hysteretic loss up to high frequencies, superior temperature stability, and a fast response time. [13] Furthermore, electrostriction is a four-rank tensor property, and thus it can be observed in all crystal symmetries. [14] Previously, the best electrostrictive materials are well known as Pb(Mg 1/3 Nb 2/3 )O 3 (PMN) relaxors with a large electrostrictive coefficient Q 33 of 0.02 m 4 C −2 . [15] Recently, some lead-free piezoelectric ceramics with relaxor behavior have exhibited the enhancement of electrostrictive effect due to their hysteresisfree characteristics. [9,11,12] On the other hand, some efforts have been employed to not only improve the electrical properties but also increase the T C of BT-based ceramics by chemical modifications, [16,17] and unfortunately most of the additives deteriorated the T C of BT-based ceramics, such as La, Gd, Sr doping in A-site [18][19][20] or Zr, Sn, Hf doping in B-site. [2,6] Based on above discussions, we want to realize the temperature-insensitive strain and the enhanced electrostrictive effect along with increasing T C by developing the material system of 0.95BaTiO 3 -0.05(M 0.5 N 0.5 )TiO 3 (M = K/Na/Li and N = Ho, Y, Yb, Ga, Nd, Pr, Sm, Gd). A distinguished temperature-insensitive strain behavior from room temperature to 130 °C is achieved in BT-(Li, Ho/Y/Yb)T. In addition, giant electrostrictive coefficient (Q 33 ) of 0.05-0.07 m 4 C −2 , which is twice larger than classical electrostrictive lead-based materials, [15] is observed in BT-(Li, Ho/Y/Yb)T ceramics over a wide temperature region. Meanwhile, inspiringly, an improved T C of 130-145 °C is achieved in BT-(K/Na/Li, Ho/Y)T six samples. A mechanism related to electrostrictive effect has been proposed to explain such an outstanding temperature insensitivity of strain property. It is believed that the giant Q 33 and the good temperature stability of strain would attract potential interest in search of novel leadfree electrostrictive materials.

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“…Dos três últimos casos observamos que a propriedade condutora do Ba 1−x La x TiO 3 vai diminuindo na medida em que a concentração de lantânio diminui. Este resultado está em concordância com os trabalhos experimentais reportados na literatura (IANCULESCU et al, 2015;STANCIU et al, 2017), esperando-se que para concentrações muito pequenas, inferiores a x = 0.005 a propriedade condutora do Ba 1−x La x TiO 3 seja perdida, caso no qual a propriedade do Ba 1−x La x TiO 3 vai ser de um material dielétrico, com propriedades ferroelétricas e sem comportamento ferromagnético. Uma análise teórica usando DFT para concentrações (x) muito pequenas precisa de processamento computacional muito pesado, com alta demanda de memória RAM e capacidade de armazenamento muito grande.…”

Section: Ba 1−x La X Tiounclassified

“…Por exemplo, o sistema Ba 1−x La x TiO 3 apresenta propriedades ferroelétricas com características semicondutoras para pequenas concentrações do dopante (x = 0.0005; 0.001, 0.003) (PULI et al, 2015). Por outro lado, analisando os efeitos da substituição de bário pelo lantânio em filmes finos (DOBAL; DIXIT; KATIYAR, 2007), grupos de pesquisa mostraram que a inclusão do La em pequenas quantidades no BaTiO 3 produz uma diminuição das suas propriedades dielétricas (IANCULESCU et al, 2015;STANCIU et al, 2017). Já em ceramicas de Ba 1−x La x Ti 1−x/4 O 3 , estudos ressaltam as características dielétricas do material, com uma alta permissividade dielétrica para x ≤ 0.20 (MORRISON;SINCLAIR;WEST, 2001).…”

Section: Introductionunclassified

Estudo teórico de sistemas ferroelétricos usando Teoria do Funcional de Densidade (DFT)

Aslla-Quispe¹

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In this work, the electronic properties of pure and modified barium titanate, with perovskite structure (ABO 3), considering trivalent rare-earth elements, which presente multifunctional characteristics with potential for practical applications. In particular, the multiferroic characteristics as well as electronic structure, have been studied as a function of the rare-earth content considering the Density Functional Theory (DFT), where the polarization of the electronic spin the the Hubbard potential have been taken into account in order to correct the electron-electron Coulumbians interactions in the partially-filled f orbitals of the rare-earth cations. The electronic properties, such as electronic structure and the states density have been calculated after the optimization of the system by using the minimization condition for the total energy. The band-structure were used in order to determine the spontaneous electric polarization, which is very important to confirm the ferroelectric nature of the crystalline systems. The total magnetization, obtained from the self-consistent calculations, is used for determining the ferromagnetic nature of the studied systems. Results show that the Ba 2+ substitution by La 3+ , considering the compensation of the crystalline structure with barium vacancies, induce the ferroelectric properties in the doped system, being those less intense that the pure tetragonal BaTiO 3. On the other hand, the Ba 2+ substitution by partially-filled 4f orbitals rare-earths, leads to the simultaneous presence of the dielectric, ferroelectric and ferromagnetic behavior, being the ferromagnetism promoted by the contribution of the 4f electrons of the rare-earth elements. This later property has been also confirmed from the result of the absorption coefficients (XANES) at the oxygen K-edge. The importance of the obtained results opens new perspectives for additional theoretical and experimental researches from the point of view of their designs and analysis of new materials, as well as revelas potential applications of the studied systems for the electro-electronic industry.

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Lanthanum influence on the structure, dielectric properties and luminescence of BaTiO 3 ceramics processed by spark plasma sintering technique

Cited by 29 publications

References 25 publications

Comparative study of spark plasma sintering features on the densification of Ni-Cr binary alloys

Comparative study of spark plasma sintering features on the densification of Ni-Cr binary alloys

Giant Electrostrictive Responses and Temperature Insensitive Strain in Barium Titanate‐Based Ceramics

Estudo teórico de sistemas ferroelétricos usando Teoria do Funcional de Densidade (DFT)

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