Infrared phonon dynamics of a multiferroic BiFeO3 single crystal
Infrared phonon dynamics of a multiferroic BiFeO3 single crystal
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DOI：
10.1103/physrevb.76.172105
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发表时间：
2007-11-01
影响因子：
3.7
通讯作者：
Colson, D.
中科院分区：
文献类型：
--
作者：
Lobo, R. P. S. M.;Moreira, R. L.;Colson, D.
本文讨论了BiFeO_3单晶在5K至室温范围内的红外反射率测量。全面而明确地确定了所预测的9个ab面E声子模。得到了四个A(1)c轴声子的频率。这些结果解决了陶瓷的理论和数据之间的问题。结果表明，最低频率E模的软化是介电常数随温度变化的原因，说明BiFeO_3的铁电相变是由软模驱动的。
We discuss the infrared reflectivity measurement on a BiFeO3 single crystal between 5 K and room temperature. The nine predicted ab-plane E phonon modes are fully and unambiguously determined. The frequencies of the four A(1) c-axis phonons are found. These results settle issues between theory and data on ceramics. Our findings show that the softening of the lowest frequency E mode is responsible for the temperature dependence of the dielectric constant, indicating that the ferroelectric transition in BiFeO3 is soft-mode driven.