Giant Electrostriction Enhanced by Substitutions in La₂Mo₂O₉ Anionic Conductors

Abstract “Giant” electrostrictors are materials that exhibit anomalously large quadratic electromechanical coupling. Few such materials have been discovered and the origin of their remarkable properties is still under debate. Here several new giant electrostrictors based on iso‐ and alio‐valent substitutions in La 2 Mo 2 O 9 are reported. The dielectric, elastic, anelastic and electrostrictive properties of La 2 Mo 2 O 9 ‐based materials are measured and show no correlation with the ionic radius of the substituent element, contrary to what has been reported for doped ceria. The substitutions on the La site affect the electrostrictive properties more than on the Mo site, opposite to their effect on the dielectric properties. No correlation is found between the anelasticity or the oxygen vacancy density and the electrostrictive properties. The mechanism underlying “giant” electrostriction in La 2 Mo 2 O 9 ‐based materials thus appears to be different from that proposed for ceria‐based materials.