Anisotropic terahertz transmission induced by the external magnetic field in La0.67Ca0.33MnO3 film

A systemic investigation of the terahertz (THz) transmission of La0.67Ca0.33MnO3 film on the (001)-oriented NdGaO3 substrate under external magnetic field and low temperature have been performed. The significant THz absorption difference between the out-of-plane and the in-plane magnetic field direction is observed, which is consistent with the electrical transport measurement using the standard four-probe technique. Furthermore, we find that the complex THz conductivities can be reproduced in terms of the Drude Smith equation as the magnetic field is perpendicular to the film plane, whereas it deviates from this model when the in-plane magnetic field is applied. We suggest that such anisotropies in THz transport dynamics have close correspondences with the phase separation and anisotropic magnetoresistance effects in the perovskite-structured manganites. Our work demonstrates that the THz time-domain spectroscopy (TDS) can be an effective non-contact method for studying the magneto-transport properties of the perovskite-structured manganites. (C) 2021 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license

本研究针对生长于(001)取向NdGaO3衬底上的La0.67Ca0.33MnO3薄膜，在外加磁场与低温条件下的太赫兹(THz)透射特性开展了系统性探究。实验观测到，面外与面内磁场方向下存在显著的太赫兹吸收差异，该结果与采用标准四探针技术的电学输运测量结果一致。进一步研究发现，当磁场垂直于薄膜平面时，复太赫兹电导率可通过德鲁德-史密斯(Drude Smith)方程拟合重现；而当施加面内磁场时，该复电导率则偏离此模型。我们认为，太赫兹输运动力学中的各向异性现象，与钙钛矿结构锰氧化物中的相分离效应及各向异性磁阻效应存在紧密关联。本研究表明，太赫兹时域光谱(THz time-domain spectroscopy, TDS)可作为一种有效的非接触式表征手段，用于研究钙钛矿结构锰氧化物的磁输运特性。© 2021 作者。除另有注明外，本文所有内容均采用知识共享署名(CC BY)许可协议进行授权。