Radiationless Transitions in the Eu3+ Center in LaAlO3

Three different types of radiationless transitions play a role in the radiationless decay of the luminescent Eu³⁺ center in LaAlO₃: (a) a temperature‐independent process from the charge‐transfer state, (b) a temperature‐dependent process $\text{(ΔE\hspace{0.17em}=\hspace{0.17em}0.15}\mathrm{eV})$ from this state, (c) a temperature‐dependent process $\text{(ΔE\hspace{0.17em}=\hspace{0.17em}1.1}\mathrm{eV})$ from the ${}^5{D}_0$ level. All three processes are of importance because the charge‐transfer state of Eu³⁺ is situated at low energies in LaAlO₃. If, however, this state is situated at higher energies, as it is in other host lattices, only process (b) will be observed in the conventional range of temperatures.