Transient photostriction and strain modulation in La, Nb-codoped BiFeO3 thin films
Coherent longitudinal acoustic phonons in Bi0.8La0.2Fe0.99Nb0.01O3 (BLFNO) films are photo-induced and detected by the femtosecond time-resolved reflectance spectroscopy. The generation mechanism of coherent longitudinal acoustic phonons is attributed to the transient photostriction effect. The strain modulation of the out-of-plane elastic properties C⊥ is realized in BLFNO films deposited on different substrates (ZrO2 and PbMg1/3Nb2/3-PbTiO3). Strain modulation of the thin film is demonstrated by applying an electromotive force on the piezoelectric substrate PbMg1/3Nb2/3-PbTiO3.