Optical and magnetic spectroscopy of rare-earth-doped yttrium aluminium borate (YAl3(BO3)(4)) single crystals

摘要

For Ce3+, Er3+ and Yb3+ ions, electron paramagnetic resonance (EPR) spectra typical for S' = 1/2 ions are measured for YAl3(BO3)(4) (YAB) single crystal. The spectra show axial symmetry indicating that all three dopants replace Y3+ at the given dopant concentration. Corresponding (g) over tilde- and hyperfine (A) over bar -tensors are determined. The EPR linewidth of Ce broadens with increasing temperature due to an Orbach relaxation process. Fitting the curve with an exponential, the energy difference is found to be equal to 270 +/- 16 cm(-1). The optical absorption and excitation spectra of Ce in YAB single crystal measured at 300 K are similar to those found for polycrystalline materials. High-resolution polarized emission from the lowest excited to the F-2(5/2) ground state, measured at 4.2 K, indicates a splitting of the ground state into three levels. The second level is located 277 +/- 18 cm(-1) above the first one, in excellent agreement with the EPR result, and the third level is located 140 +/- 10 cm(-1) above the second one. [References: 9]