TRLFS of Eu3+ and Cm3+ doped La2Zr2O7: A comparison of defect fluorite to pyrochlore structures

Abstract

Time-resolved laser fluorescence spectroscopy (TRLFS) was used to probe the local environment of Eu3+ and Cm3+ doped into La2Zr2O7 in both the defect fluorite and pyrochlore structures. It is evident that each structure has a dominant environment for the trivalent dopant ion. This makes it possible to characterize the fluorescence emission spectrum and lifetime for each Eu3+ and Cm3+ species. This data can be used for a relative quantification of the Eu3+ or Cm3+ in each local environment. This technique has application to verifying single phase material and probing radiation damage, and has been shown to be more sensitive than the current evaluation method of X-ray diffraction. The defect fluorite structure has a poorly defined site due to random oxygen vacancies and a short fluorescence lifetime, while the pyrochlore structure has a well defined emission and long fluorescence lifetime. The Cm3+ fluorescence from the pyrochlore structure was found to have a greater bathochromic shift (red shift) and larger ground state splitting of the 8S7/2 than previously reported in any system.