Subsolidus solution and electrical properties of Sr-substituted bismuth magnesium niobate pyrochlores |
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Affiliation: | 1. Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia;2. Department of Mechanical and Material Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, 43000 Bandar Sungai Long, Kajang, Selangor, Malaysia;3. Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia;1. Volgograd State Social Pedagogical University, 27 Lenin Avenue, Volgograd 400131, Russia;2. Volgograd State Technical University, 28 Lenin Avenue, Volgograd 400131, Russia;1. College of Material Science and Engineering, Guilin University of Electronic Technology, Guilin, 541004, PR China;2. Guangxi Key Laboratory of Information Materials, Guilin University of Electronic Technology, Guilin, 541004, PR China;1. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, 430070, PR China;2. International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, 430070, PR China;1. Department of Information Engineering, Guilin University of Aerospace Technology, Guilin 541004, PR China;2. College of Material Science and Engineering, Central South University, Changsha 410083, PR China;3. College of Material Science and Engineering, Guilin University of Electronic Technology, Guilin 541004, PR China;1. WZ AMI of HUST, Wenzhou, 325035, PR China;2. School of Optical and Electronic Information, Key Lab of Functional Materials for Electronic Information (B) of MOE, Huazhong University of Science and Technology, Wuhan, 430074, PR China;3. Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, PR China |
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Abstract: | Here we investigated the structural and dielectric properties of (Bi3.36Mg0.64-xSrx)(Mg1.28Nb2.72)O13.76 (0≤ x≤0.5) subsolidus solution. Sr-substituted bismuth magnesium niobate (BMSN) pyrochlores were prepared by solid-state reaction at 1025 °C over 1–2 days. X-ray diffraction (XRD) analysis confirmed that the BMSN pyrochlores crystallise in cubic symmetry, space group Fd3m with lattice parameters in the range 10.5968 (4)-10.5671 (17) Å. The surface morphologies of these samples, as confirmed by Scanning Electron Microscopy (SEM), were composed of irregular shaped grains. Both Scherrer and Williamson-Hall methods revealed that the crystallite sizes were in the range 46–75 nm. No thermal event was discernible over the temperature range 30–1000 °C, thus confirming the thermal stability of these materials. On the other hand, Arrhenius conductivity plots showed the BMSN pyrochlores to be highly insulating with activation energies of ~1.20–1.49 eV. At ~30 °C and 1 MHz, BMSN pyrochlores exhibited moderate high bulk dielectric constants, ɛ’, 90–186 and low dielectric losses, tan δ in the order of 10−2–10−1, respectively. Both the ɛ’ and tan δ values of the BMSN pyrochlores showed a nearly two-fold decrease with increasing Sr concentration. Negative temperature coefficient of capacitances, TCC, −408 to −713 ppm/°C were recorded over ~30–300 °C at 1 MHz. |
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Keywords: | Pyrochlore Niobate Compounds Dielectric constants Dielectric losses |
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