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Crystal structure and microwave dielectric properties of (1 − x)NdAlO3-xCaTiO3 ceramics |
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| Authors: | Min-Han KimChang-Soo Woo Sahn Nahm Chang-Hack ChoiHwack-Joo Lee Hyun-Min Park |
| Affiliation: | a Department of Materials Science and Engineering, Korea University, 1-5 Ka, Anam-Dong, Sungbuk-Ku, Seoul 136-701, South Korea b Advanced Materials Technology, 17-2 Jamwon-Dong, Seocho-Ku, Seoul 137-030, South Korea c New Materials Evaluation Center, Korea Research Institute of Standards and Science, Taeduk Science Town, Taejon 305-600, South Korea |
| Abstract: | Crystal structure and microwave dielectric properties of (1−x)NdAlO3-xCaTiO3 ceramics have been investigated. Crystal structure of the specimens changed with the composition. Rhombohedral structure was found for the specimens with x≤0.1. When 0.3≤x≤0.7, the specimens had the tetragonal structure and it changed to the orthorhombic structure as x exceeded 0.7. Two types of the second phases were observed in (1−x)NdAlO3-xCaTiO3 ceramics. For the specimens with x≤0.5, Nd4Al2O9 phase was observed and Al-rich phase was found in the specimens with x≥0.7. The dielectric constant (εr) and the temperature coefficient of the resonant frequency (τf) increased with the increase of x. The Q×f value of the specimen increased with x and exhibited the maximum value when x=0.5. The microwave dielectric properties of Q×f=45,000 GHz, εr=45 and τf=−1.5 ppm/°C were obtained for 0.3NdAlO3-0.7CaTiO3 ceramics. |
| Keywords: | A. Ceramics A. Electronic materials C. X-ray diffraction D. Dielectric properties |
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