Non-classical electrostriction in calcium-doped cerium oxide ceramics

Oxygen-defective metal oxides, e.g. , acceptor-doped CeO 2 , demonstrate exceptionally large electrostrictive responses compared to state-of-the-art electromechanically active ceramic materials. Oxygen-defective metal oxides, e.g. , acceptor-doped CeO 2 , demonstrate exceptionally large electrostrictive responses compared to state-of-the-art electromechanically active ceramic materials. Recent investigations focus on trivalent acceptor (A 3+ ) doped ceria and surmise that giant electrostriction on these compounds depends on the electroactive polarizable elastic dipoles associated with electronic defects in the lattice, e.g. , oxygen vacancies and polarons. Similarly, to relaxor piezoelectrics, electromechanical responses in doped-ceria strictly depend on the applied field frequency, i.e. , time-dependent, revealing a complex interplay between the electro-chemo-mechanic effect in the materials and a loss of properties above 1–10 Hz. This work demonstrates the electromechanical properties of divalent (A 2+ ) calcium-doped ceria (CDC) polycrystalline ceramics with various doping levels (Ce 1− x Ca x O 2− x , x = 0.025–0.15). All the CDC compounds illustrate a steady and high electrostrictive strain coefficient ( M 33 ) value exceeding 10 −18 m 2 V −2 across frequencies between 10 −1 and 10 3 Hz. Notably, the M 33 is slightly influenced by the nominal oxygen vacancy concentration, CaO segregation, and the microstructure. These key findings unveil a new form of electromechanical effects in calcium-doped ceria that are rigorously stimulated by the strong electro-steric interaction of pairs.