Temperature dependent terahertz giant anisotropy and cycloidal spin wave modes in BiFeO3 single crystal  

作　　者：Fan Liu Zuanming Jin Xiumei Liu Yuqing Fang Jiajia Guo Yan Peng Zhenxiang Cheng Guohong Ma Yiming Zhu 刘凡;金钻明;刘秀梅;方雨青;国家嘉;彭滟;程振祥;马国宏;朱亦鸣(Shanghai Key Laboratory of Modern Optical System,and Engineering Research Center of Optical Instrument and System(Ministry of Education),University of Shanghai for Science and Technology,Shanghai 200093,China;Department of Physics,Shanghai University,Shanghai 200444,China;Institute for Superconducting and Electronic Materials,University of Wollongong,NSW,Australia;SIOM&STU Joint Laboratory for Superintense Lasers and the Applications,Shanghai 201210,China;Shanghai Institute of Intelligent Science and Technology,Tongji University,Shanghai 200092,China)

机构地区：[1]Shanghai Key Laboratory of Modern Optical System,and Engineering Research Center of Optical Instrument and System(Ministry of Education),University of Shanghai for Science and Technology,Shanghai 200093,China [2]Department of Physics,Shanghai University,Shanghai 200444,China [3]Institute for Superconducting and Electronic Materials,University of Wollongong,NSW,Australia [4]SIOM&STU Joint Laboratory for Superintense Lasers and the Applications,Shanghai 201210,China [5]Shanghai Institute of Intelligent Science and Technology,Tongji University,Shanghai 200092,China

出　　处：《Chinese Physics B》2020年第7期135-140,共6页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant Nos.61975110,11674213,61735010,and 11604202);the 111 Project,China(Grant No.D18014);the International Joint Lab Program supported by Science and Technology Commission Shanghai Municipality,China(Grant No.17590750300);the Key Project supported by Science and Technology Commission Shanghai Municipality,China(Grant No.YDZX20193100004960);Science and Technology Commission of Shanghai Municipality,China(Shanghai Rising-Star Program 18QA1401700);Shanghai Educational Development Foundation,China(Chen Guang Project 16CG45).

摘　　要：THz time-domain spectroscopy(THz-TDS)is used to study the THz-optical properties of a single crystal bismuth ferrite BiFeO3(BFO).It can be found that the anisotropy of BiFeO3 is strongly dependent on the temperature.A giant birefringence up to around 3.6 is observed at 1 THz.The presence of a spatially modulated cycloidal antiferromagnetic structure leads to spin cycloid resonances(SCR)ψandΦ,corresponding to the out-of-plane and in-plane modes of the spin cycloid,respectively.We distinguish the SCR with respect to their response to orthogonal polarizations of the electric fields of the incident THz beam.In addition,we observe a resonance appearing below 140 K,which might be interpreted as an electromagnon mode and related to a spin reorientation transition.Our present observations present that the temperature and polarization,as the external control parameters,can be used to modulate the THz optical properties of BFO single crystal.

关 键 词：time resolved terahertz spectroscopy dielectric anisotropy spin cycloid resonance 

分 类 号：TM277[一般工业技术—材料科学与工程] O433[电气工程—电工理论与新技术]