Orientation Dependence of Elastic and Piezoelectric Properties in Rhombohedral BiFeO3

摘要

Through a coordinate transformation approach, crystal orientation dependences of elastic and piezoelectric properties at room temperature have been investigated in a three-dimensional space for rhombohedral bismuth ferrite (BiFeO3). Elastic constants (stiffnesses) c11′, c12′, c13′ and piezoelectric constants d15′, d31′, d33′ along arbitrary orientations were obtained based on crystalline asymmetry characteristics of 3m point group BiFeO3. Parameters along specific orientations obtaining the largest values were presented. The max c11′ = 213 × 10⁹ N/m² could be achieved in planes with ϕ = 0° and 90°. The max c12′ = c13′ = 132.2 × 10⁹ N/m² could be achieved along directions at θ = 13° and θ = 77° inside three mirror planes, respectively. The max d15′ = 27.6 × 10⁻¹² C/N and the max d31′ = 12.67 × 10⁻¹² C/N could be both obtained along directions at θ = 69° inside mirror planes. The max d33′ = 18 × 10⁻¹² C/N could be obtained at θ = 0°, along the spontaneous polarization axis. By adopting optimal directions, the elastic and piezoelectric parameters of BiFeO3 could be significantly enhanced which shows applications for the growth of BeFeO3 films with preferred orientations and enhanced properties.