Structural and electrical properties of SrBi2V x Nb2−x O9 ferroelectric ceramics: Effect of temperature and frequency

Abstract

Aurivillius type bismuth layered materials have received a lot of attention because of their application in ferroelectric non-volatile random access memories. Among bismuth layer structured ferroelectric ceramics SrBi 2 Ta 2 O 9 (SBT)/SrBi 2 Nb 2 O 9 (SBN) are of great interest for researchers because of their fatigue resistance and less distorted structure. Recently vanadium substitution in SBN/SBT has shown interesting electric and dielectric properties. In the present work, processing conditions, microstructure and electrical studies of vanadium doped SBN ferroelectric ceramics have been performed. Samples of compositions SrBi 2 V x Nb 2-x O 9 , x=0.0, 0.1, 0.3, 0.5 were prepared by solid-state reaction technique using high purity oxides / carbonates. The samples were calcined at 700°C and sintered at 800°C. X-ray diffractograms show that a single phase layered perovskite structure is formed in all the samples. Effect of partial substitution of pentavalent niobium ion (0.68 Å) by smaller pentavalent vanadium ion (0.59 Å) at B site on the microstructure, Curie temperature, Dielectric constant, Dielectric loss and electrical conductivity have been investigated. Dielectric properties of SBVN have been investigated from room temperature to 500°C and frequency of 100 Hz to 1 MHz. Dielectric constant values at their respective Curie points are observed to increase with increasing vanadium concentration. Curie temperature is observed to be maximum in x=0.1 vanadium doped sample. Strong relaxor like dielectric relaxation at the transition temperatures have been observed. With increasing vanadium concentration the dielectric loss is observed to increase significantly. It is also observed that dielectric loss increases with increase in temperature. The variation of conductivities in these samples is also reported.

Synthesis and Ferroelectric Properties of Bi4.5Sr0.5Ti4Fe0.5-xVxO15Ceramics

“…When comparing the P r value of the sample at x = 0.03 with that of the sample at x = 0, the improvement in the P r value was recognized by the V substitution, though the remarkable differences in the E c values of the samples at x = 0 and 0.03 was not observed. In the case of small amount of V-substituted ferroelectric materials, it is reported that the ratting in the BO 6 octahedron in the [A n-1 B n O 3n+1 ] 2− perovskite block which relates with the structural distortion and the improvement in the sinterability enhances the ferroelectric properties of the materials [6,12]. The temperature dependences of dielectric constant of BSTVF at 1 MHz are shown in Fig.…”

Optical Properties, Electronic Structures, and Photocatalytic Performances of Bandgap-Tailored SrBi2Nb2−xVxO9 Compounds

“…SrBi 2 Nb 2 O 9 (SBN) compounds with layered perovskite structures are of great interest in the fields of dielectrics, ferroelectrics, and photocatalysts [15][16][17][18]; for instance, Shu et al investigated their electronic band structures, relaxation energies, and bonding mechanisms by using the first-principle calculation, showing that the ferroelectric properties of SBN compounds mainly originated from the covalent effect between B-site cations and oxygen ions, which was enhanced by Bi-O hybridization [19]. Li et al prepared ABi 2 Nb 2 O 9 (A = Ca, Sr, and Ba) compounds and analyzed their electronic band 2 of 9 structure, optical properties, and photocatalytic water-splitting activity (under UV light); in this case, SBN exhibited much higher activity than the other two compounds (i.e., CaBi 2 Nb 2 O 9 and BaBi 2 Nb 2 O 9 ) because its lattice was more distorted, and the angle between their corner-linked NbO 6 octahedra was closer to 180 • than the others [20].…”

Structural and Electrical Properties of Lanthanide Substituted-Bismuth Titanate Prepared by Low-Temperature Combustion Synthesis

“…This is significantly due to substitution of Nd and La in BIT system. According to Jain and Jha, the loss of Bi at high temperature is accompanied by the formation of intrinsic defects such as bismuth and oxygen vacancies [11]. Therefore the stability bismuth layered structure is sustained with the addition of Nd and La.…”