Mansouri S, Jandl S, Roberge B, Balli M, Dimitrov D Z, Orlita M, Faugeras C
Université de Sherbrooke, Département de Physique, 2500 Boulevard Université, Sherbrooke, Canada J1K 2R1.
J Phys Condens Matter. 2016 Feb 10;28(5):055901. doi: 10.1088/0953-8984/28/5/055901. Epub 2016 Jan 20.
We have studied the Raman and infrared spectral response of TbMn2O5 under an applied magnetic field parallel to the easy magnetic a-axis at 4.2 K. Strong spin-lattice coupling in TbMn2O5 is evidenced by a frequency shift of Raman and infrared phonons as a function of magnetic field compared to the phonon response of BiMn2O5 that remains unaffected. The magnetic field behavior of the highest frequency phonons retraces the polarization switching in TbMn2O5 and shows an important frequency softening below 3 T that is modulated by the J 3 and J 4 exchange parameters. The role of the Tb(3+) spin alignment with H is interpreted in terms of a local lattice striction and the contribution of the charge transfer mechanism to the magnetoelectric process is evaluated.
我们研究了在4.2 K下，与易磁化a轴平行的外加磁场中TbMn2O5的拉曼光谱和红外光谱响应。与未受影响的BiMn2O5的声子响应相比，TbMn2O5中拉曼声子和红外声子的频率随磁场变化，这证明了TbMn2O5中存在强自旋-晶格耦合。最高频率声子的磁场行为重现了TbMn2O5中的极化切换，并在3 T以下显示出重要的频率软化，该软化由J3和J4交换参数调制。从局部晶格收缩的角度解释了Tb(3+)自旋与H的排列作用，并评估了电荷转移机制对磁电过程的贡献。
