Luminescence of Eu³⁺ Ion in Antiferromagnetic KMnF₃ Crystals

The emission and excitation spectra of Eu 3+ ion doped in antiferromagnetic KMnF 3 crystals are investigated at low temperatures. It is suggested from the characteristics of emission spectrum that Eu 3+ ion occupies Mn 2+ ion site. Several magnon sidebands are found in the spectrum of the emission due to \(⁵D₀{}⁷F₂\) transition. Both magnon creation and annihilation sidebands are observed. The temperature dependence of their emission intensities at very low temperature region is interpreted in term of the boson particle nature of magnon. The interacting magnons are considered to be of the resonance mode of KMnF 3 host lattice. The efficiency of the energy transfer process from 4 T 1 state of Mn 2+ ion to 5 D 0 state of Eu 3+ ion strongly depends on temperature. This is interpreted on the basis of the assumption that the Frenkel type exciton associated with 4 T 1 state of Mn 2+ ion is bound at the Mn 2+ ion perturbed by a nearby Eu 3+ ion and energy transfer takes place between these Mn 2+ and Eu 3+ ions.