Recoverable strain studies of gadolinium-doped multiferroic BiFeO3 by ultrasonic velocity measurements

Single-phase multiferroic bismuth ferrite samples doped with gadolinium with compositional formulae Bi1–xGdxFeO3 (x = 0, 0.05, 0.10, 0.15, & 0.20) have been prepared by the modified solid-state reaction technique. The well-known pulse transmission method was used to measure ultrasonic velocities at four different frequencies. The elastic moduli were calculated using the velocity values at four different frequencies. The elastic moduli were also corrected to their zero porosity using Hasselman and Fulrath model. The observed variation of elastic moduli with varying concentration of Gd and at different frequencies has been explained. Finally, as these materials are having the shape memory applications, their recoverable strain values were also calculated and the results are compared with those available in the literature.