naa a22 4500 510801005 CHVBK 20180411083355.0 cr unu---uuuuu 180411e20130601xx s 000 0 eng 10.1007/s11664-013-2567-2 doi (NATIONALLICENCE)springer-10.1007/s11664-013-2567-2 Dielectric and Impedance Spectroscopy of Barium Orthoniobate Ceramic [Elektronische Daten] [Biswajit Pati, R.N.P. Choudhary, Piyush Das, B.N. Parida, R. Padhee] Barium orthoniobate (Ba3Nb2O8), a derivative of the perovskite family, was prepared using a high-temperature solid-state reaction technique (calcination temperature=1425°C and sintering temperature=1450°C for 4h). Preliminary x-ray structural analysis with room-temperature x-ray diffraction data confirmed the formation of a single-phase compound with hexagonal crystal structure. Study of the microstructure of a gold-coated pellet by scanning electron microscopy (SEM) showed that the sample has well-defined grains that are distributed uniformly throughout the surface of the sample. Detailed studies showed that the dielectric parameters (ε r and tanδ) of the compound at three different frequencies (10kHz, 100kHz, and 1000kHz) are almost constant in the low-temperature region (from room temperature to about 200°C). An anomaly in the relative permittivity (ε r) (∼357°C) suggests the possible existence of a ferroelectric-paraelectric phase transition of diffuse type in the material. Detailed studies of impedance and related parameters show that the electrical properties of the material are strongly dependent on temperature, showing good correlation with its microstructure. The bulk resistance (evaluated from impedance studies) is found to decrease with increasing temperature. This shows that the material has negative temperature coefficient of resistance (NTCR), similar to that of semiconductors. Studies of electric modulus indicate the presence of a hopping conduction mechanism in the system with nonexponential-type conductivity relaxation. The nature of the variation of the direct-current (dc) conductivity with temperature confirms the Arrhenius and NTCR behavior in the material. The alternating-current (ac) conductivity spectra show a typical signature of an ionic conducting system and are found to obey Jonscher's universal power law. TMS, 2013 Electroceramics nationallicence impedance analysis nationallicence bulk resistance nationallicence electric modulus analysis nationallicence Pati Biswajit Department of Physics, Institute of Technical Education and Research, SOA University, Bhubaneswar, India aut Choudhary R.N.P. Department of Physics, Institute of Technical Education and Research, SOA University, Bhubaneswar, India aut Das Piyush Department of Physics, Institute of Technical Education and Research, SOA University, Bhubaneswar, India aut Parida B.N. Department of Physics, Institute of Technical Education and Research, SOA University, Bhubaneswar, India aut Padhee R. Department of Physics, Institute of Technical Education and Research, SOA University, Bhubaneswar, India aut Journal of Electronic Materials Springer US; http://www.springer-ny.com 42/6(2013-06-01), 1225-1234 0361-5235 42:6<1225 2013 42 11664 https://doi.org/10.1007/s11664-013-2567-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11664-013-2567-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Pati Biswajit Department of Physics, Institute of Technical Education and Research, SOA University, Bhubaneswar, India aut NATIONALLICENCE 700 1- Choudhary R.N.P. Department of Physics, Institute of Technical Education and Research, SOA University, Bhubaneswar, India aut NATIONALLICENCE 700 1- Das Piyush Department of Physics, Institute of Technical Education and Research, SOA University, Bhubaneswar, India aut NATIONALLICENCE 700 1- Parida B.N. Department of Physics, Institute of Technical Education and Research, SOA University, Bhubaneswar, India aut NATIONALLICENCE 700 1- Padhee R. Department of Physics, Institute of Technical Education and Research, SOA University, Bhubaneswar, India aut NATIONALLICENCE 773 0- Journal of Electronic Materials Springer US; http://www.springer-ny.com 42/6(2013-06-01), 1225-1234 0361-5235 42:6<1225 2013 42 11664 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer