From normal ferroelectric transition to relaxor behavior in Aurivillius ferroelectric ceramics

Debye’s temperature and heat capacity for Sr0.15Ba0.85Bi2Nb2O9 relaxor ferroelectric ceramic

“…The powders were pressed uniaxially by using 200 MPa and sintered in a closed alumina crucible at 1100 C for 1 h. A density value higher than 97% of the theoretical density values was obtained. The structural analysis by using X-ray diffraction 5 has showed an orthorhombic structure with the space group A2 1 am. The refined atomic data, which was obtained from using the X-ray diffraction pattern, has showed the mixing of different elements into A sites of the perovskite blocks and bismuth sites in the layered structure.…”

“…The refined atomic data, which was obtained from using the X-ray diffraction pattern, has showed the mixing of different elements into A sites of the perovskite blocks and bismuth sites in the layered structure. 5 The studied system has also been evaluated concerning dielectric, piezoelectric, pyroelectric and ferroelectric properties. 5,13,14 The differential scanning calorimetry (DSC) measurements were performed between 40 C and 500 C in argon atmosphere (Netzsch 404C with TASC 414/4 controller).…”

“…[1][2][3][4][5] However, despite their very attractive physical properties, the identification of the nature of the dielectric response in relaxor systems still remains open and requires additional theoretical and experimental information, which can be very interesting to contribute to the explanation of the origin of the observed anomalies.…”

“…5,12 The increase of the compositional disorder has been analyzed as the main cause for the relaxor behavior. 5 It has been shown by using the refined atomic data that there is a mixing of different elements into A sites and bismuth sites in the layered structure. An increase of the frequency dispersion degree has also been observed with the increasing of the barium concentration.…”

“…An increase of the frequency dispersion degree has also been observed with the increasing of the barium concentration. 5 The present paper shows the heat capacity measurement results, which has been carried out on Sr 0:15 Ba 0:85 Bi 2 Nb 2 O 9 relaxor ferroelectric ceramic in order to study thermodynamic properties of this lead-free ferroelectric system.…”