Impact of antiferromagnetism on the optical properties of rare-earth nickelates
Impact of antiferromagnetism on the optical properties of rare-earth nickelates
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反铁磁性对稀土镍酸盐光学性质的影响
DOI：
10.1103/physrevb.96.045120
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发表时间：
2017
影响因子：
3.7
通讯作者：
D. van der Marel
中科院分区：
文献类型：
--
作者：
J. Ruppen;J. Teyssier;I. Peil;S. Catalano;M. Gibert;J. Triscone;A. Georges;D. van der Marel
研究了在反铁磁有序化温度T_{N}$附近，不同成分和应变的稀土镍酸盐薄膜的光学电导率随温度的变化关系。两个突出的峰值在0.6和1.3 eV，这是绝缘相的特性，显示一个小的，但显着的强度增加时，材料从帕拉通过反铁磁。这一观察结果表明，反铁磁（AF）和键的反铁磁（BD）秩序之间的正反馈的存在。通过分析T N附近的温度依赖性，并利用BD和AF阶的Landau型自由能表达式，我们推断BD阶是AF相出现的必要条件，反铁磁性有助于键结稳定.这个模型也解释了为什么磁滞是特别强的过渡到绝缘状态时，同时发生反铁磁秩序。
We study the temperature dependence of the optical conductivity of rare-earth nickelate films of varying composition and strain close to the antiferromagnetic ordering temperature, ${T}_{N}$. Two prominent peaks at 0.6 and 1.3 eV, which are characteristic of the insulating phase, display a small but significant increase in intensity when the material passes from para- to antiferromagnetic. This observation indicates the presence of a positive feedback between antiferromagnetic (AF) and bond disproportionation (BD) order. By analyzing the temperature dependence near ${T}_{N}$, and using a Landau-type free-energy expression for BD and AF order, we infer that BD order is a necessary condition for the AF phase to appear, and that the antiferromagnetism contributes to stabilization of the bond disproportionation. This model also explains why hysteresis is particularly strong when the transition into the insulating state occurs simultaneously with antiferromagnetic order.