Realization of sensible peak shift thermometry from multiple site occupied Eu³⁺ ions in magnetically frustrated SrGd₂O₄

Magnetically frustrated lattices even at low temperatures are well-known for not minimizing interaction energies. In a magnetically frustrated structure like strontium gadolinium oxide (SrGd₂O₄), there exists more than one suitable site for rare-earth doping due to availability of two low Gd³⁺ site symmetries. In the present work SrGd₂O₄ doped with Eu³⁺ ions were prepared by solid-state reaction method. Structural characterization confirms the nature of structure and bonding. Existence of different sites in the host lattice for the doped Eu³⁺ ions were observed via excitation spectra. Photoluminescence studies with varying temperature (15–300 K) have been extensively used with high-resolution to distinguish different sites in this structure. Studies confirm that apart of the Gd³⁺ sites, Sr²⁺ could also accommodate the Eu³⁺ ions. Variation of temperature that leads to shift in emission spectral peak positions has been thoroughly examined for line shift temperature sensing applicability. Low temperature uncovers emission peaks from ⁵D₁ level that are unprovable at room temperature. Maximum relative sensitivity of ⁵D₀ → ⁷F₀ peak intensity to one of the multiple sites in SrGd₂O₄:Eu³⁺ has been found to be 12.08 × 10^–3% K⁻¹ while using McCumber-Sturge equation to quantify line shift.