resumo
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 D-5(1) level that are unprovable at room temperature. Maximum relative sensitivity of D-5(0) -> F-7(0) peak intensity to one of the multiple sites in SrGd2O4:Eu3+ has been found to be 12.08 x 10(-3)% K-1 while using McCumber-Sturge equation to quantify line shift.
palavras-chave
ENERGY-TRANSFER; OPTICAL-PROPERTIES; LUMINESCENCE; EUROPIUM(III); GD
categoria
Materials Science
autores
Pavani, K; Jamalaiah, BC; Neves, AJ; Soares, MJ; Shim, J; Nagajyothi, PC; Pinto, RJB; Graca, MPF; Jakka, SK
nossos autores
Bungala Chinna Jamalaiah
Bolseiro de pós-Doutoramento
Ricardo Pinto
Investigadoragradecimentos
K.P. and S.K.J acknowledges the funding by national funds (OE), through FCT-FundacAo para a Ciencia e a Tecnologia, Portugal, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. This work was developed within the scope of the project i3N, UIDB/50025/2020 &UIDP/50025/2020, financed by national funds through the FCT/MEC. Jaesool Shim acknowledges the National Research Foundation of Korea (2020R1A4A1019227 and 2020R1A2C1012439) for the financial support. The authors thank Dr. Ricardo J.B. Pinto, CICECO, Department of Chemistry, University of Aveiro for his help in STEM characterization.