Effects of Rare‐Earth Dopants on the Ferroelectric and Pyroelectric Properties of Strontium Barium Niobate Ceramics

Abstract

Effects of various rare-earth (RE) dopants (Y 31 , La 31 , Ce 31 , Pr 31 , Nd 31 , Sm 31 , Eu 31 , Gd 31 , Tm 31 , Dy 31 , Er 31 , and Yb 31 ) on the dielectric, ferroelectric, and pyroelectric properties of Sr 0.5 Ba 0.5 Nb 2 O 6 (SBN50) ceramics were investigated. In the present studies, the doping concentrations of all the RE dopants were fixed at 1 mol%. Their potential usefulness in pyroelectric applications was discussed based on their measured pyroelectric detectivity figure of merit (FOM). On the basis of our studies, for RE dopants with atomic numbers smaller than Nd, their dielectric constants were greatly increased, while for RE dopants with atomic numbers larger than Sm, their dielectric constants as well as dielectric losses became smaller. Among various dopants, Eu-doped SBN showed the most improved ferroelectric properties. Its remnant polarization (P r ) was increased to 4.86 mC/cm 2 as compared with 3.23 mC/cm 2 obtained in undoped SBN50. On the other hand, Gd-doped SBN exhibited the largest pyroelectric coefficient of 168 mC/m 2 K, which was over three times of that of the undoped sample (49 mC/m 2 K). The work shows that Gd-doped SBN exhibits the greatest potential for pyro-applications because it bears the largest FOM of 0.45 Â 10 À5 Pa À0.5 [Correction: After online publication on 11/05/2008, an error was found in this article. The original value, 1.35 Â 10 À5 Pa À0.5 , was incorrect. The data has been replaced with the correct value.].

Effects of stress on the optical properties of epitaxial Nd-doped Sr0.5Ba0.5Nb2O6 films

“…Details of the target preparation process were given elsewhere. 17 For thin film preparation, a KrF excimer laser (Lambda Physik COMPex205, 248 nm, 20 ns) was used. Laser energy density of 4 J/cm 2 , pulsed laser repetition rate of 5 Hz, oxygen pressure of 200 mTorr (∼ 26 Pa), substrate temperature of 700…”

“…Using the Bragg diffraction equation, the c-lattice constants were determined to be 3.97 Å, which is slightly larger than that of the bulk sample (3.94 Å). 17 The full-width at half-maximum (FWHM) values of the (002) peaks were 0.40…”

“…Secondly, the crystal structure of SBN ('unfilled' tetragonal tungsten bronze) 17 is more disordered as compared to that of the PZT (pseudo-cubic).…”

Effects of BaO sintering additive on dielectric properties of Y2Ti2O7 microwave dielectric ceramics

“…Y 2 Ti 2 O 7 microwave dielectric ceramics possess A 2 B 2 O 7 pyrochlore structure. The physical properties of most materials can be adjusted by modifying their composition, such as varying the A/B ratio or introducing dopants [7]. Researches [8][9][10][11] indicate that doping with suitable ions is far more efficient and convenient in modifying the physical properties of Y 2 Ti 2 O 7 ceramics compared with changing the A/B ratio.…”

Electrocaloric effect of alkali co-substituted Sr0.6Ba0.4Nb2O6 ceramics

“…To obtain better pyroelectric properties, Sr x Ba 1-x Nb 2 O 6 system was doped with various cations e.g. Y 3+ , La 3+ , Ce 3+ , Pr 3+ , Nd 3+ , Sm 3+ , Eu 3+ , Gd 3+ , Tm 3+ , Dy 3+ , Er 3+ , Yb 3+ , K + and Na + [23,24]. Yao et al [23] reported that pyroelectric properties of Sr 0.5 Ba 0.5 Nb 2 O 6 increase with the Gd 3+ dopant from 49 μC/m 2 K to 168 μC/m 2 K at room temperature however the origin of this improvement was not discussed.…”