Effect of ferromagnetic and ferroelectric properties on the sound velocity anomaly in BiFeO3

• Published in: Journal of alloys and compounds Vol. 685; pp. 978 - 982
• Main Authors: Cao, Xian-Sheng, Ji, Gao-Feng, Jiang, Xing-Fang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.11.2016
• Subjects: Anharmonic phonon-phonon interaction; Ferromagnetic and ferroelectric properties; Sound velocity; Ferromagnetic and ferroelectric properties; Anharmonic phonon-phonon interaction; Sound velocity
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2016.06.138

The effect of ferromagnetic and ferroelectric properties on the sound velocity in multiferroic BiFeO3 (BFO) is studied with using Green’s function method on the basis of the magnetoelectric coupling, the spin-phonon interaction and the anharmonic phonon-phonon interaction. The Heisenberg-like model is employed to describe the magnetic subsystem, and the transverse Ising model is used to explain the ferroelectric subsystem. The reduced velocity is obtained in the limit of zero wave vectors. It is shown that the reduced velocity of sound of BiFeO3 exhibits a cusp-like at the magnetic phase transition temperature TN. This anomaly in reduced velocity can be explained as an influence of vanishing magnetic ordering above TN and the ferroelectric subsystem can not be influenced by the magnetic subsystem above TN due to TN ≪ TC in the BFO. The reduced velocity and TN increase with increasing of the J1, J2 and g, whereas reduced velocity decreases with I increases. The achieved conclusion is in accordance with the experimental results. •The sound velocity in BiFeO3 is studied with using Green’s function method.•The reduced velocity of sound of BiFeO3 exhibits a cusp-like at TN.•The reduced velocity and TN increase with increasing of the J1, J2 and g.•The reduced velocity decreases with I increases.