Phonon thermal transport and phonon–magnon coupling in polycrystalline BiFeO3 systems. (19th February 2015)

• Record Type: Journal Article
• Authors: Ramachandran, B; Wu, K K; Kuo, Y K; Ramachandra Rao, M S
• Is Part Of: Journal of physics. Volume 48:Number 11(2015)
• Publication Date: 2015-02-19
• Subjects: multiferroics -- phonon thermal transport -- phonon–magnon coupling; Physics -- Periodicals; 530
• DOI: 10.1088/0022-3727/48/11/115301
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: Temperature-dependent thermal conductivity of polycrystalline BiFeO3, Bi0.9 Ba0.05 Ca0.05 FeO2.95 and Bi0.9 Ca0.1 FeO2.95 materials was measured using a direct heat pulse technique. Thermal conductivity of the BiFeO3 -based materials is analyzed using a phonon model to probe the thermal transport mechanisms in these ferrites. It is found that the calculated thermal conductivity of the BiFeO3 -based compounds is in good agreement with experimental data. The suppression of the low-temperature phonon peak in the thermal conductivity of the doped BiFeO3 materials is mainly attributed to the phonon-point-defect scattering. In addition, the contribution of optical phonon–magnon resonance scattering to optical phonon thermal transport reveals the presence of phonon–magnon coupling in these BiFeO3 materials. Finally, magneto-thermal conductivity measurements show the magnon thermal transport in pure and doped BiFeO3 systems.