Thickness dependent dielectric properties of calcium copper titanate ceramics measured in a controlled atmosphere |
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| Affiliation: | 1. Physical Chemistry Department, Chemistry Institute, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil;2. Advanced Materials Department, Jo?ef Stefan Institute, Ljubljana, Slovenia;1. School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China;2. School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070, China;1. Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand;2. Synchrotron Light Research Institute (Public Organization), 111 University Avenue, Muang District, Nakhon Ratchasima 30000, Thailand;3. Institute of Nanomaterials Research and Innovation for Energy (IN–RIE), NANOTEC–KKU RNN on Nanomaterials Research and Innovation for Energy, Khon Kaen University, Khon Kaen 40002, Thailand;1. Hunan Engineering Laboratory for Preparation Technology of Polyvinyl Alcohol Fiber Materials, College of Chemistry and Materials Engineering, Huaihua University, Huaihua 418000, PR China;2. Shenzhen Key Laboratory of New Lithium-Ion Battery and Mesoporous Materials, College of Chemistry and Chemical Engineering, Shenzhen University, Shenzhen 518060, PR China;3. College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009, PR China;4. College of Biological and Food Engineering, Huaihua University, Huaihua 418000, PR China;5. Department of Materials and Engineering, Wuxi Institute of Arts and Technology, Yixing 214206, PR China |
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| Abstract: | Phase pure CaCu3Ti4O12 CCTO ceramics are prepared by solid-state synthesis route. The effect of measuring atmospheres (air and dry N2) on the stability and reproducibility of electrical properties of CCTO as a function of sample thickness (as-prepared to thinned down) is investigated. As-sintered CCTO prepared at 1080 °C for 5 h with an initial thickness of 2.31–2.32 mm is reduced subsequently by fine grinding to 1.835 mm and then to 1.65–1.5 mm. Large inconsistency in the impedance spectra is observed when the samples are measured in air despite the thickness variations. Stable and reproducible dielectric properties are obtained in dry N2. A relatively closer resistivity (～2 × 108 Ωcm at 23 °C in N2) regardless of the sample thickness suggests the absence of any barrier layer at the sample surface. Increased space charge accumulation at grain boundaries (GBs) leading to much larger dielectric constant (ε′) was observed in air at 23 °C. A temperature (from 23 °C to 225 °C) and frequency (from 1 Hz to 1 MHz) independent and stable ε′ is observed when samples are tested in N2. Much lower tan δ values with large ε′ are observed for both as prepared (0.010 ± 0.001 with ε′ of 9,663 ± 4 at 1.4 kHz) and the thinned down (0.015 ± 0.000 with ε′ of 9,352 ± 5 and 4.5 kHz) samples at 23 °C in N2. |
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| Keywords: | Processing Dielectric properties Atmosphere Capacitor Calcium copper titanate Thickness effect Low loss |
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