Luminescence of Eu³⁺ Ion in Antiferromagnetic KMnF₃ Crystals

Abstract

The emission and excitation spectra of Eu³⁺ ion doped in antiferromagnetic KMnF₃ crystals are investigated at low temperatures. It is suggested from the characteristics of emission spectrum that Eu³⁺ ion occupies Mn²⁺ ion site. Several magnon sidebands are found in the spectrum of the emission due to (Remark: Graphics omitted.) 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 KMnF₃ host lattice. The efficiency of the energy transfer process from ⁴T₁ state of Mn²⁺ ion to ⁵D₀ state of Eu³⁺ ion strongly depends on temperature. This is interpreted on the basis of the assumption that the Frenkel type exciton associated with ⁴T₁ state of Mn²⁺ ion is bound at the Mn²⁺ ion perturbed by a nearby Eu³⁺ ion and energy transfer takes place between these Mn²⁺ and Eu³⁺ ions.