Large Nonclassical Electrostriction in (Y, Nb)‐Stabilized δ‐Bi₂O₃

Abstract

Classical electrostriction, describing a second‐order electromechanical response of insulating solids, scales with elastic compliance, S, and inversely with dielectric susceptibility, ε. This behavior, first noted 20 years ago by Robert Newnham, is shown to apply to a wide range of electrostrictors including polymers, glasses, crystalline linear dielectrics, and relaxor ferroelectrics. Electrostriction in fluorite ceramics of (Y, Nb)‐stabilized δ‐Bi2O3 is examined with 16%–23% vacant oxygen sites. Given the values of compliance and dielectric susceptibility, the electrostriction coefficients are orders of magnitude larger than those expected from Newnham's scaling law. In ambient temperature nanoindentation measurements, (Y, Nb)‐stabilized δ‐Bi2O3 displays primary creep. These findings, which are strikingly similar to those reported for Gd‐doped ceria, support the suggestion that ion conducting ceramics with the fluorite structure, a large concentration of anion vacancies and anelastic behavior, may constitute a previously unknown class of electrostrictors.

Giant Electrostriction Enhanced by Substitutions in La2Mo2O9 Anionic Conductors

“…[ 33 ] Our results show a maximum enhancement for Gd‐LAMOX (isovalent substitution, hence with the same oxygen vacancy concentration as La 2 Mo 2 O 9 ) while K‐LAMOX with higher oxygen vacancy concentration (aliovalent substitution) does not exhibit “giant” electrostriction. This is in contrast with previous studies on Bi 7 Nb 2−x Y x O 15.5−x [ 14 ] that indicated a positive correlation between “giant” electrostriction and the fraction of oxygen vacancies. Nevertheless, our results agree with the absence of such a correlation as already observed in doped ceria.…”

“…The presence of anelasticity is therefore not sufficient to ensure a "giant" electrostrictive response. This is consistent with the anelastic properties of doped-ceria [5] or Bi 7 Nb 2−x Y x O 15.5−x ceramics presenting primary creep, [14] whereas 8 mol% Yttria Stabilized Zirconia (8YSZ) polycrystalline samples exhibit anelastic relaxation [52] without exhibiting "giant" electrostriction.…”

Non‐Classical Electrostriction in Hydrated Acceptor Doped BaZrO3: Proton Trapping and Dopant Size Effect

“…All samples contracted in the direction of the applied field ( M 33 < 0). This is similar to the observations for acceptor doped ceria and bismuth oxide, [ 2,6,11 ] both of which have a fluorite structure, but it is contrary to the most conventional electrostrictors (with perovskite or other structure). The samples exhibited strain saturation with an electric field, and electromechanical relaxation with frequency.…”

The role of oxygen defects on the electro-chemo-mechanical properties of highly defective gadolinium doped ceria

“…Fig. 3 shows that all samples strained negatively at the second harmonic of the applied electric field, verifying the electrostriction behavior of ceria, as reported in [2] [4]. A large strain is noticed for low-doped samples that contain large blocking barrier effect (α g.b.…”