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Thermal behavior and characteristic of submicron sized barium titanate ceramic synthesized by acetylacetonate precursor
Author’s Accepted Manuscript Thermal behavior and characteristic of submicron sized barium titanate ceramic synthesized by acetylacetonate precursor W.X. Zhang, L.Q. Li, P. Li www.elsevier.com/locate/ceri
PII: DOI: Reference:
S0272-8842(18)30992-1 https://doi.org/10.1016/j.ceramint.2018.04.119 CERI18036
To appear in: Ceramics International Received date: 11 February 2018 Revised date: 3 April 2018 Accepted date: 14 April 2018 Cite this article as: W.X. Zhang, L.Q. Li and P. Li, Thermal behavior and characteristic of submicron sized barium titanate ceramic synthesized by acetylacetonate precursor, Ceramics International, https://doi.org/10.1016/j.ceramint.2018.04.119 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Thermal behavior and characteristic of submicron sized barium titanate ceramic synthesized by acetylacetonate precursor W.X. Zhang*, L.Q. Li, P. Li School of Electrical and Electronic Engineering of Shangqiu Normal University, Shangqiu, 476000, China
*Corresponding author. E-mail address: [email protected] ABSTRACT This article reports the synthesis of tetragonal and submicron sized BaTiO3 (BTO) ceramic prepared by Ba(acac)2 and TiO(acac)2 precursors. The thermal behavior and characteristic of BaTiO3 ceramic were investigated by TG/DTA analyzer, XRD, SEM, Raman spectrum and ferroelectric property analyses. The results show that the thermal decomposition process of TiO(acac)2 finished earlier than that of Ba(acac)2. The thermal reaction of the mixed precursors completed approximately at 800°C. The results of the XRD and Raman spectrum analysis reveal that the product is tetragonal BTO ceramic. The SEM micrograph shows that the grain size of the BTO ceramic is 200–420nm and the average size is 330nm. The electric hysteresis loop of the submicron BTO ceramic shows a remanence and saturation polarization of 4.7 and 5.3μC/cm2, respectively. The BTO ceramic prepared in this study display favorable ferroelectric properties at the submicron level, which make it suitable for applications in microelectronic devices.
Keywords: Submicron BTO ceramics; Thermal behavior; Acetylacetonate precursor; Tetragonal 1. Introduction Perovskite phase BTO has attracted a strong scientific interest in the last 50 years owing to its high dielectric constant, low dielectric loss, excellent ferroelectricity and piezoelectricity, and optical properties [1–5]. BTO is one of the most widely used perovskite structure materials and has been used in multilayer ceramic capacitors, dynamic random access memory devices, tunable microwave devices, gas sensors, nanogenerators, and electro–optical devices in the electronics industry [6–11]. For example, as a ceramic capacitors, BTO has its irreplaceable advantages. It can provide a high charge and discharge speed, and almost unlimited cycle times, which are desirable for energy storage applications in various power circuits. In recent years, with the development of miniatue and portableelectronic equipment, the size of the electronic device has become more important. To meet the need for smaller devices, the grain size of BTO ceramic materials need to be controlled in the submicron range. Typical perovskite BTO ceramics have been prepared by the solid state method, sol–gel method, hydrothermal reaction, microwave synthesis, oxalate route synthesis and spray pyrolysis [12–17]. The BTO ceramics prepared with different methods display different kind properties. Generally, the dielectric constant of BTO ceramic depends on the grain size, shape, crystalline phase, doping, Ba/Ti ratio, and materials coated on the BTO., Furthermore, the increase of the tetragonality can leads to an enhancement of the dielectric constant, which is caused by the
1
asymmetry of the crystal structure. Acetylacetone are a special group organometallic compounds, which undergo a complex decomposition reaction under heating conditions, along with exothermic and endothermic processes. The final products are almost metal oxide. The mixing and heating of two or more acetylacetone would release a significant amount of energy, which would promote and accelerate their decomposition and interreaction. In this study, we report the first synthesis of BTO ceramic from acetylacetonate precursors. Submicron and tetragonal BTO ceramics can be prepared through a simple decomposition reaction procedure. The structure, morphology, optical and dielectric properties of the BTO ceramic were characterized by X–ray diffracometert, scanning electron microscopy, Raman spectroscopy and a ferroelectric test system. 2. Experimental All of the chemical reagents were analytical grade and used as received without further purification. First, 0.01mol TiO(acac)2 and 0.01mol Ba(acac)2·2H2O were added into a PTFE beaker, and 10ml ethyl alcohol and 10ml deionized water were added to the beaker. The above solution was mixed with constant stirring for 10 min, then transferred to a vacuum drying oven and kept for 2 h at room temperature. For thermal decomposition analysis, a small quantity of the dried product, pure TiO(acac)2 and Ba(acac)2·2H2O were transferred to a platinum crucible. For the BTO ceramic, the obtained product was ground and then pressed into tablets with a thickness of 1–2 mm and a diameter of 10 mm. Finally, the tablets were sintered at a heating rate of 10°C/min and kept at 1000°C for 2 h in air. The thermal decomposition behavior of acetylacetonate precursors was analyzed by thermal gravimetric and differential thermal analysis (TG and DTA, Shimadzu TGA–50). The obtained sintered samples were characterized by X–ray diffraction (XRD, Bruker D8 Advance Cu Kα radiation), scanning electron microscopy (SEM, JSM–7001F) and Raman spectroscopy (Renishaw, R–1000) with a 532 nm laser excitation. The polarization field (P–E) hysteresis was measured with a ferroelectric and pyroelectric test system (Radiant Technologist Inc). 3. Results and discussion Fig. 1 shows the TG curves of pure TiO(acac)2 and Ba(acac)2 precursors sintered from room temperature to 1300°C at a heating rate of 10°C/min. It can be seen both TG curves decrease quickly from room temperature to approximately 450°C, which indicates that the main decomposition reaction occurred in this temperature range. The weight loss curve of TiO(acac)2 gradually become stable over 450°C. Compared with TiO(acac)2, the decomposition reaction of the Ba(acac)2 precursor can be observed in the temperature range of 900–1090°C. This indicates that the TiO2 crystalline phase formed earlier than the BaO phase. Fig. 2 gives the TG/DTA curves of the mixture of Ba(acac)2 and TiO(acac)2 precursors heated from room temperature to 1200°C. It is obvious that the TG curve of the mixture is different to that of pure Ba(acac)2 and TiO(acac)2. A major weight loss of ~50% occurs between 50°C and 230°C, and a further weight loss of ~10% is evident up to 800°C. Compared with Fig. 1, the mainly decomposition reaction of the mixture of the two precursors happens earlier than pure Ba(acac)2 and TiO(acac)2, and no obvious weight loss can be observed above 800°C. Which indicates that the reaction process of precursors can be accelerated by the released heat of them. The reaction between the two precursors is also reflected in the DTA curve, including an
2
endothermic peak at 50°C and two big exothermic peaks at 220°C, and 360°C caused by the decomposition and interreaction of mixture of precursors. The TG /DTA curves are consistent with each other and become two stable lines from 800°C to 1200°C. The interreaction between Ba(acac)2 and TiO(acac)2 precursors mostly finish and the BTO crystalline structure becomes stable at about 800°C. The formation mechanism of BTO is generally dependent on the formation of the first crystalline phase. In this reaction, the TiO2 crystalline phase appears earlier than the BaO phase, and the TiO2 particles grow until the BaO at the surface of the TiO2 enter into the lattice. Fig. 3 shows the XRD pattern of the BTO ceramic sintered at 1000°C for 2h. All the diffraction peaks in this pattern can be indexed quite well to a tetragonal BTO (JCPDS No: 05−2626) unit cell with lattice parameters of a=3.99Å, c=4.04Å with a space group of P4mm. No peak corresponding to an impurity phase is observed. To accurately identify the tetragonal BTO phase, a magnification of the 44.6−46° 2θ range was carefully analyzed. The inset in Fig. 3 gives the reflections of (002) and (200) peaks of the BTO ceramic. The splitting of the reflections in this region is a result of the distortion of the tetragonal BTO unit cell, which confirms that the as– prepared BTO ceramic has a fine tetragonal structure [18,19]. Moreover, the tetragonal structure also can be conformed by Raman spectrum. When a cubic symmetry structure is distorted, the resulting non-centrosymmetric tetragonal structure leads to Raman active modes. Fig. 4 shows the Raman spectrum of the as-synthesized BTO ceramic sample. In accordance with the literature, the five bands that appear at 182, 254, 306, 520 and 719 cm-1 assigned to the A1, A1, B1+E, E+A1, and A1+ E modes. The Raman peak at 306 cm-1 is associated with an asymmetry within the TiO6 octahedra [20–23]. If a tetragonal phase is dominant, the Raman peak will be stronger [24–26]. In Fig. 4, it is clear that the band at 306cm-1 is sharp and strong. On the basis of the XRD and Raman spectrum analysis, the BTO ceramic has a highly crystalline tetragonal structure. Fig. 5 shows the microstructure of the BTO ceramic sample at a low and high magnification. As shown in the SEM images, the sample exhibits a cubic shape, and the grain size is estimated to be approximately 200–420nm with a narrow grain size distribution obtained by the intercept line method, the average size is approximately 330nm. Fig. 6 gives the hysteresis loop of the BTO ceramic sintered at 1000°C for 2 h. A maximum remanence of 4.7μC/cm2 and saturation polarization of 5.3μC/cm2 is obtained for the submicron sized BTO ceramic. The ferroelectricity of BTO can be influenced by the grain size and structural symmetry, BTO can not exhibit ferroelectricity when the crystal size below 44nm. The value of the BTO ceramic prepared by acetylacetonate precursor is favorable ferroelectric properties in submicron level and the polarization result is consistent with the XRD and Raman spectrum results. 4. Conclusions In summary, submicron sized and tetragonal BTO ceramic was prepared successfully by a facile thermal decomposition reaction technique. The reaction speed can be accelerated by the released heat of acetylacetonate precursors and the grain growth can be limited with a shorter heat treatment time. The results show that the thermal decomposition process of TiO(acac)2 finished earlier than that of Ba(acac)2. The thermal reaction of the mixed precursors completed approximately at 800°C. The results of the XRD and Raman spectrum analysis reveal that the product is tetragonal BTO ceramic. The SEM micrograph shows that the grain size of the BTO
3
ceramic is 200–420nm and the average size is 330nm. The electric hysteresis loop of the submicron BTO ceramic shows a remanence and saturation polarization of 4.7 and 5.3μC/cm2, respectively. The experimental results conform that the BTO ceramic prepared in this study display favorable ferroelectric properties at the submicron level, which make it suitable for applications in microelectronic devices. Acknowledgements The authors thank the National Natural Science Foundation of China (U1404115) and Henan Province Educational Committee Program (16A140032) for financial support.
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[15] Y. Ma, E. Vileno, S.L. Suib, P.K. Dutta Synthesis of tetragonal BaTiO3 by microwave heating and conventional heating, Chem. Mater. 9 (1997) 3023–3031. [16] H.S. Potdar, S.B. Deshpande, S.K. Date, Chemical coprecipitation of mixed (Ba+Ti) oxalates precursor leading to BaTiO3 powders, Mater. Chem. Phys. 58 (1999) 121–127. [17] K.K. Lee, Y.C. Kang, K.Y. Jung, J.H. Kim, Preparation of nano-sized BaTiO3 particle by citric acid–assisted spray pyrolysis, J. Alloys Compd. 395 (2005) 280–285. [18] T.T. Xu, C.A. Wang, Effect of two-step sintering on micro–honeycomb BaTiO3 ceramics prepared by freeze– casting process, J. Eur. Ceram. Soc. 36 (2016) 2647–2652. [19] M. Ganguly, S.K. Rout, T.P. Sinha, S.K. Sharma, H.Y. Park, C.W. Ahn, I.W. Kim, Characterization and rietveld refinement of A–site deficient lanthanum doped barium titanate, J. Alloys. Compd. 579 (2013) 473– 484. [20] H. Hayashi, T. Nakamura, T. Ebina, In-situ Raman spectroscopy of BaTiO3 particles for tetragonal–cubic transformation, J. Phys. Chem. Solids. 74 (2013) 957–962. [21] F. Maxim, P. Ferreira, P.M. Vilarinho, A. Aimable, P. Bowen, Additive–Assisted Aqueous Synthesis of BaTiO3 Nanopowders, Cryst. Growth. Des. 10 (2010) 3996–4004. [22] J. Yang, J. Zhang, C.Y. Liang, M. Wang, P.F. Zhao, M.M. Liu, J.W. Liu, R.C. Che, Ultrathin BaTiO3 Nanowires with High Aspect Ratio: A Simple One–Step Hydrothermal Synthesis and Their Strong Microwave Absorption, ACS Appl. Mater. Interfaces. 5 (2013) 7146–7151. [23] R. Asiaie, W.D. Zhu, S.A. Akbar, P.K. Dutta, Characterization of Submicron Particles of Tetragonal BaTiO3, Chem. Mater. 8 (1996) 226–234. [24] R.J. Li, W.X. Wei, J.L. Hai, L.X. Gao, Z.W. Gao, Y.Y. Fan, Preparation and electric–field response of novel tetragonal barium titanate, J. Alloy Compd. 574 (2013) 212–216. [25] D. Gulwade, P. Gopalan, Diffuse phase transition in La and Ga doped barium titanate, Solid. State. Commun.146 (2008) 340–344. [26] M. Özen, M. Mertens, F. Snijkers, P. Cool, Hydrothermal synthesis and formation mechanism of tetragonal barium titanate in a highly concentrated alkaline solution, Ceram. Int. 42 (2016) 10967–10975.
Fig. 1 TG curves of Ba(acac)2 and TiO(acac)2 precursors calcined from room temperature to 1300°C.
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Fig. 2 TG/DTA curves of the mixture of Ba(acac)2 and TiO(acac)2 precursors calcined from room temperature to 1200°C.
Fig. 3 XRD patterns of BTO ceramic prepared by acetylacetonate precursor sintered at 1000°C for 2h.
Fig. 4 Raman spectrum of BTO ceramic prepared by acetylacetonate precursors.
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Fig. 5 SEM images of BTO ceramic with low and high magnification.
Figure 6. P-E loops of submicron BTO ceramic measured at room temperature.
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PII: DOI: Reference:
S0272-8842(18)30992-1 https://doi.org/10.1016/j.ceramint.2018.04.119 CERI18036
To appear in: Ceramics International Received date: 11 February 2018 Revised date: 3 April 2018 Accepted date: 14 April 2018 Cite this article as: W.X. Zhang, L.Q. Li and P. Li, Thermal behavior and characteristic of submicron sized barium titanate ceramic synthesized by acetylacetonate precursor, Ceramics International, https://doi.org/10.1016/j.ceramint.2018.04.119 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Thermal behavior and characteristic of submicron sized barium titanate ceramic synthesized by acetylacetonate precursor W.X. Zhang*, L.Q. Li, P. Li School of Electrical and Electronic Engineering of Shangqiu Normal University, Shangqiu, 476000, China
*Corresponding author. E-mail address: [email protected] ABSTRACT This article reports the synthesis of tetragonal and submicron sized BaTiO3 (BTO) ceramic prepared by Ba(acac)2 and TiO(acac)2 precursors. The thermal behavior and characteristic of BaTiO3 ceramic were investigated by TG/DTA analyzer, XRD, SEM, Raman spectrum and ferroelectric property analyses. The results show that the thermal decomposition process of TiO(acac)2 finished earlier than that of Ba(acac)2. The thermal reaction of the mixed precursors completed approximately at 800°C. The results of the XRD and Raman spectrum analysis reveal that the product is tetragonal BTO ceramic. The SEM micrograph shows that the grain size of the BTO ceramic is 200–420nm and the average size is 330nm. The electric hysteresis loop of the submicron BTO ceramic shows a remanence and saturation polarization of 4.7 and 5.3μC/cm2, respectively. The BTO ceramic prepared in this study display favorable ferroelectric properties at the submicron level, which make it suitable for applications in microelectronic devices.
Keywords: Submicron BTO ceramics; Thermal behavior; Acetylacetonate precursor; Tetragonal 1. Introduction Perovskite phase BTO has attracted a strong scientific interest in the last 50 years owing to its high dielectric constant, low dielectric loss, excellent ferroelectricity and piezoelectricity, and optical properties [1–5]. BTO is one of the most widely used perovskite structure materials and has been used in multilayer ceramic capacitors, dynamic random access memory devices, tunable microwave devices, gas sensors, nanogenerators, and electro–optical devices in the electronics industry [6–11]. For example, as a ceramic capacitors, BTO has its irreplaceable advantages. It can provide a high charge and discharge speed, and almost unlimited cycle times, which are desirable for energy storage applications in various power circuits. In recent years, with the development of miniatue and portableelectronic equipment, the size of the electronic device has become more important. To meet the need for smaller devices, the grain size of BTO ceramic materials need to be controlled in the submicron range. Typical perovskite BTO ceramics have been prepared by the solid state method, sol–gel method, hydrothermal reaction, microwave synthesis, oxalate route synthesis and spray pyrolysis [12–17]. The BTO ceramics prepared with different methods display different kind properties. Generally, the dielectric constant of BTO ceramic depends on the grain size, shape, crystalline phase, doping, Ba/Ti ratio, and materials coated on the BTO., Furthermore, the increase of the tetragonality can leads to an enhancement of the dielectric constant, which is caused by the
1
asymmetry of the crystal structure. Acetylacetone are a special group organometallic compounds, which undergo a complex decomposition reaction under heating conditions, along with exothermic and endothermic processes. The final products are almost metal oxide. The mixing and heating of two or more acetylacetone would release a significant amount of energy, which would promote and accelerate their decomposition and interreaction. In this study, we report the first synthesis of BTO ceramic from acetylacetonate precursors. Submicron and tetragonal BTO ceramics can be prepared through a simple decomposition reaction procedure. The structure, morphology, optical and dielectric properties of the BTO ceramic were characterized by X–ray diffracometert, scanning electron microscopy, Raman spectroscopy and a ferroelectric test system. 2. Experimental All of the chemical reagents were analytical grade and used as received without further purification. First, 0.01mol TiO(acac)2 and 0.01mol Ba(acac)2·2H2O were added into a PTFE beaker, and 10ml ethyl alcohol and 10ml deionized water were added to the beaker. The above solution was mixed with constant stirring for 10 min, then transferred to a vacuum drying oven and kept for 2 h at room temperature. For thermal decomposition analysis, a small quantity of the dried product, pure TiO(acac)2 and Ba(acac)2·2H2O were transferred to a platinum crucible. For the BTO ceramic, the obtained product was ground and then pressed into tablets with a thickness of 1–2 mm and a diameter of 10 mm. Finally, the tablets were sintered at a heating rate of 10°C/min and kept at 1000°C for 2 h in air. The thermal decomposition behavior of acetylacetonate precursors was analyzed by thermal gravimetric and differential thermal analysis (TG and DTA, Shimadzu TGA–50). The obtained sintered samples were characterized by X–ray diffraction (XRD, Bruker D8 Advance Cu Kα radiation), scanning electron microscopy (SEM, JSM–7001F) and Raman spectroscopy (Renishaw, R–1000) with a 532 nm laser excitation. The polarization field (P–E) hysteresis was measured with a ferroelectric and pyroelectric test system (Radiant Technologist Inc). 3. Results and discussion Fig. 1 shows the TG curves of pure TiO(acac)2 and Ba(acac)2 precursors sintered from room temperature to 1300°C at a heating rate of 10°C/min. It can be seen both TG curves decrease quickly from room temperature to approximately 450°C, which indicates that the main decomposition reaction occurred in this temperature range. The weight loss curve of TiO(acac)2 gradually become stable over 450°C. Compared with TiO(acac)2, the decomposition reaction of the Ba(acac)2 precursor can be observed in the temperature range of 900–1090°C. This indicates that the TiO2 crystalline phase formed earlier than the BaO phase. Fig. 2 gives the TG/DTA curves of the mixture of Ba(acac)2 and TiO(acac)2 precursors heated from room temperature to 1200°C. It is obvious that the TG curve of the mixture is different to that of pure Ba(acac)2 and TiO(acac)2. A major weight loss of ~50% occurs between 50°C and 230°C, and a further weight loss of ~10% is evident up to 800°C. Compared with Fig. 1, the mainly decomposition reaction of the mixture of the two precursors happens earlier than pure Ba(acac)2 and TiO(acac)2, and no obvious weight loss can be observed above 800°C. Which indicates that the reaction process of precursors can be accelerated by the released heat of them. The reaction between the two precursors is also reflected in the DTA curve, including an
2
endothermic peak at 50°C and two big exothermic peaks at 220°C, and 360°C caused by the decomposition and interreaction of mixture of precursors. The TG /DTA curves are consistent with each other and become two stable lines from 800°C to 1200°C. The interreaction between Ba(acac)2 and TiO(acac)2 precursors mostly finish and the BTO crystalline structure becomes stable at about 800°C. The formation mechanism of BTO is generally dependent on the formation of the first crystalline phase. In this reaction, the TiO2 crystalline phase appears earlier than the BaO phase, and the TiO2 particles grow until the BaO at the surface of the TiO2 enter into the lattice. Fig. 3 shows the XRD pattern of the BTO ceramic sintered at 1000°C for 2h. All the diffraction peaks in this pattern can be indexed quite well to a tetragonal BTO (JCPDS No: 05−2626) unit cell with lattice parameters of a=3.99Å, c=4.04Å with a space group of P4mm. No peak corresponding to an impurity phase is observed. To accurately identify the tetragonal BTO phase, a magnification of the 44.6−46° 2θ range was carefully analyzed. The inset in Fig. 3 gives the reflections of (002) and (200) peaks of the BTO ceramic. The splitting of the reflections in this region is a result of the distortion of the tetragonal BTO unit cell, which confirms that the as– prepared BTO ceramic has a fine tetragonal structure [18,19]. Moreover, the tetragonal structure also can be conformed by Raman spectrum. When a cubic symmetry structure is distorted, the resulting non-centrosymmetric tetragonal structure leads to Raman active modes. Fig. 4 shows the Raman spectrum of the as-synthesized BTO ceramic sample. In accordance with the literature, the five bands that appear at 182, 254, 306, 520 and 719 cm-1 assigned to the A1, A1, B1+E, E+A1, and A1+ E modes. The Raman peak at 306 cm-1 is associated with an asymmetry within the TiO6 octahedra [20–23]. If a tetragonal phase is dominant, the Raman peak will be stronger [24–26]. In Fig. 4, it is clear that the band at 306cm-1 is sharp and strong. On the basis of the XRD and Raman spectrum analysis, the BTO ceramic has a highly crystalline tetragonal structure. Fig. 5 shows the microstructure of the BTO ceramic sample at a low and high magnification. As shown in the SEM images, the sample exhibits a cubic shape, and the grain size is estimated to be approximately 200–420nm with a narrow grain size distribution obtained by the intercept line method, the average size is approximately 330nm. Fig. 6 gives the hysteresis loop of the BTO ceramic sintered at 1000°C for 2 h. A maximum remanence of 4.7μC/cm2 and saturation polarization of 5.3μC/cm2 is obtained for the submicron sized BTO ceramic. The ferroelectricity of BTO can be influenced by the grain size and structural symmetry, BTO can not exhibit ferroelectricity when the crystal size below 44nm. The value of the BTO ceramic prepared by acetylacetonate precursor is favorable ferroelectric properties in submicron level and the polarization result is consistent with the XRD and Raman spectrum results. 4. Conclusions In summary, submicron sized and tetragonal BTO ceramic was prepared successfully by a facile thermal decomposition reaction technique. The reaction speed can be accelerated by the released heat of acetylacetonate precursors and the grain growth can be limited with a shorter heat treatment time. The results show that the thermal decomposition process of TiO(acac)2 finished earlier than that of Ba(acac)2. The thermal reaction of the mixed precursors completed approximately at 800°C. The results of the XRD and Raman spectrum analysis reveal that the product is tetragonal BTO ceramic. The SEM micrograph shows that the grain size of the BTO
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ceramic is 200–420nm and the average size is 330nm. The electric hysteresis loop of the submicron BTO ceramic shows a remanence and saturation polarization of 4.7 and 5.3μC/cm2, respectively. The experimental results conform that the BTO ceramic prepared in this study display favorable ferroelectric properties at the submicron level, which make it suitable for applications in microelectronic devices. Acknowledgements The authors thank the National Natural Science Foundation of China (U1404115) and Henan Province Educational Committee Program (16A140032) for financial support.
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Fig. 1 TG curves of Ba(acac)2 and TiO(acac)2 precursors calcined from room temperature to 1300°C.
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Fig. 2 TG/DTA curves of the mixture of Ba(acac)2 and TiO(acac)2 precursors calcined from room temperature to 1200°C.
Fig. 3 XRD patterns of BTO ceramic prepared by acetylacetonate precursor sintered at 1000°C for 2h.
Fig. 4 Raman spectrum of BTO ceramic prepared by acetylacetonate precursors.
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Fig. 5 SEM images of BTO ceramic with low and high magnification.
Figure 6. P-E loops of submicron BTO ceramic measured at room temperature.
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