Directly probing spin dynamics in insulating antiferromagnets using ultrashort terahertz pulses
Directly probing spin dynamics in insulating antiferromagnets using ultrashort terahertz pulses
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DOI：
10.1103/physrevb.94.184429
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发表时间：
2016-11-22
影响因子：
3.7
通讯作者：
Prasankumar, R. P.
中科院分区：
文献类型：
--
作者：
Bowlan, P.;Trugman, S. A.;Prasankumar, R. P.
我们研究自旋动力学反铁磁多铁性TbMnO 3使用光泵，太赫兹（THz）探测光谱。光激发导致宽带THz透射变化，在10 K下的起始时间为25 ps，在较高温度下变得更快。我们把这个时间常数归因于自旋晶格热化。我们的测量和以前的超快共振x射线衍射测量之间的良好协议，在相同的材料证实，我们的太赫兹脉冲直接探测自旋序。此外，在磁有序温度以上的泵浦-探测信号的存在表明，与共振X射线探测不同，太赫兹透射对短程自旋序的动态敏感，这在像TbMnO 3这样的自旋螺旋多铁性中是重要的。
We investigate spin dynamics in antiferromagnetic multiferroic TbMnO3 using optical-pump, terahertz (THz)-probe spectroscopy. Photoexcitation results in a broadband THz transmission change, with an onset time of 25 ps at 10 K that becomes faster at higher temperatures. We attribute this time constant to spin-lattice thermalization. The excellent agreement between our measurements and previous ultrafast resonant x-ray diffraction measurements on the same material confirms that our THz pulse directly probes spin order. Furthermore, the presence of a pump-probe signal above the magnetic ordering temperatures suggests that, unlike resonant x-ray probing, THz transmission is sensitive to the dynamics of short-range spin order, which is known to be of importance in spin-spiral multiferroics like TbMnO3.