Zr and Sn substituted (Na_0.5Bi_0.5)TiO₃–based solid solutions

Abstract

Formation of phases during the solid state synthesis of the [(Na 0.5 Bi 0.5 ) 0.80 Bа 0.20 ](Ti 1−у B у )O 3 system of solid solutions, with substitutions of zirconium and tin ions for titanium ones, has been investigated. It is demonstrated that the synthesis is a multi-step process which is accompanied by the formation of a number of intermediate phases (depending on the composition of the solid solution and the temperature of synthesis). Single phase solid solutions have been manufactured when the sintering temperature was increased to 1000 -1100 °C.An increase of the concentration of the substituting ions results in a linear increase in the size of the crystal cell. As a consequence the reduction of the tolerance factor and an increase of the stability of the antiferroelectric phase with respect to the ferroelectric one take place.

Dimensional t-factor variation and increase of stability of the ferroelectric state in (Na0.5Bi0.5)TiO3-based solid solutions

“…31,32 This is due to the Ti 4þ and Zr 4þ ions have the largest dimension difference of among all the replacing ions studied in the present paper.…”

“…The results of such substitutions have been discussed in details. 31,32 In the [(Na 0:5 Bi 0:5 ) 0:80 B 0:20 ](Ti 1Ày Zr y )O 3 (the Zr ionic radius is larger than the one of titanium) solid solutions with different zirconium content, the two phase transitions were clearly observed. The first of them (the low temperature one) corresponds to the FE-AFE phase transition and the second one corresponds to the transition from the AFE (nonpolar) to the PE phase (the attribution of phases was made according to Refs.…”

“…[27][28][29][30] As expected, the AFE state in BNT-BT was also stabilized when the substitutions of ions with a size larger than the size of the Ti þ4 -ion took place. 31 5,33 This compound undergoes a phase transition from the FE state into the AFE state when heated and has a subsequent phase transition into the PE state at higher temperatures. We have also studied solid solutions with smaller barium content located in the vicinity of the morphotropic region.…”

On the high temperature phase transition in Ba(Zr0.20Ti0.80)O3ceramic

“…14 Investigations have been taken up world-wide with different aims on the solid solutions of BZT with other materials like: (Ba,Ca)TiO 3 , [15][16][17][18][19] (Bi 1=2 Na 1=2 ÞTiO 3 , [20][21][22][23] 29 NiO, 30 Ni, 31 polyvinyl alcohol, 32 epoxy, 33 Portland cement, 34,35 etc. Further, materials having high dielectric constant (10 3 -10 6 Þ are considered to be important nowadays keeping in view the growing interest in the fields of aeronautic, aerospace, power plants, automotive industries, oil and natural gas industries, various critical components' evaluation in nuclear industries, hybrid or electrically powered vehicles, thermal and geothermal engineering, etc.…”

Engineering the nature of polarization dynamics in lead-free relaxors based on (Bi1/2Na1/2)TiO3

“…This could explain why the Zr 4+ and Sn 4+ with the same charge but different size from Ti 4+ can also achieve similar effects. 27 Previously, Ts was interpreted as a threshold between different dielectric relaxation processes. 7,28 The frequency dispersion below Ts originates from the thermal evolution of two coexisting PNRs with respectively R3c and P4bm phase, while the frequency independent Tm represents the structural transition from R3c to P4bm.…”