深紫外光谱研究

高频无极汞灯采用电磁感应耦合激励汞泡发光的方法,具有稳定性好、寿命长、发光强度大等优点,广泛应用于原子吸收光谱分析,紫外消毒以及环境污染监测等领域。高频无极汞灯辐射最强的紫外谱线为253.7nm,采用汞灯照射样品,检测样品对该谱线的吸收谱,可检测样品中汞的含量以及环境中汞污染程度。我们研究了高频无极汞灯辐射253.7nm谱线幅度随着汞泡冷端温度的变化,得出了该谱线辐射最强时的温度,作为汞灯的最佳工作温度。     

Spontaneous magnetization and resistivity jumps in bilayered manganite （La0.8Eu0.2）4/3Sr5/3Mn2O7 single crystals

Owing to the inhomogeneous state resulting from the doping of a small number of Eu ions into Laa/3Sr5/3Mn2O7, from the resulting single crystal （La0.8Eu0.2）a/3Sr5/3Mn2O7 we have observed the magnetization jump, the resistivity jump, as well as the relaxation phenomena. For （Lao.sEuo.2）a/3Sr5/3Mn2O7, it has a very delicate ground state due to the interplays among spin, charge, orbital, lattice degrees of freedom. Consequently, the magnetization state is sensitive to temperature, magnetic field, as well as time. Meanwhile, the evolution of the magnetization with time shows a spontaneous jump when both the temperature and the magnetic field are constant. Similar step-like behaviours are also observed in resistivity. All these results suggest that Eu doping can greatly modulate the physical properties of Laa/3Sr5/3Mn2O7 and cause such interesting behaviours.