Temperature-Dependent Raman Spectrum of Hexagonal YMnO3 Films Synthesized by Chemical Solution Method

We study the temperature-dependent Raman spectrum of hexagonal YMnO3 films prepared by a chemical solution method. There are seven Raman peaks （3A1 ＋ E1 ＋ 4E2） of the film identified at room temperature. From the results of temperature dependence of the Raman spectrum, it is deduced that the YMnO3 film has a magnetic phase transition temperature of about 123K. The temperature variation phonon mode at 685cm^-1 shows an anomalous frequency variation near 123 K, suggesting either a more complex mechanism of spin-phonon coupling or strong mixing of phonon modes. The reason for the higher antiferromagnetic Néel temperature TN of the film than that of the bulk counterpart is also discussed.     

环己烷/水界面自组装纳米银膜及性能研究

在环己烷/水界面以自组装的方式将单层密排的银纳米粒子膜转移到亲水性的硅片上,以罗丹明6G(R6G)为探针分子,通过与直接滴加银胶溶液和混合R6G后的银胶溶液得到的两种SERS基底对比,密排银纳米粒子膜展现了极高的灵敏度(R6G的检测极限为10-9 mol/L)和信号再现性。结合有限时域差分法(FDTD)对其增强原因进行了模拟分析,实验结果与理论模拟基本相符。