INVESTIGATION OF THE HEAT CAPACITY OF Y_3-xEu_xSc₂Ga₃O₁₂ (0 < x < 3) SOLID SOLUTIONS

Denisova L.T., Irtyugo L.A.

Siberian Federal University

660041, Krasnoyarsk, Svobodnyi pr. 79

Yttrium-scandium-gallium garnet is a promising material for high-efficiency phosphors. Similar ionic radii, identical charge, and close electronegativity of Eu³⁺ and Y³⁺ ions facilitate lattice doping, enabling Y³⁺ substitution and solid solution formation. Substituting Y³⁺ with Eu³⁺ has the potential to enhance the luminescent properties of this material. However, the thermodynamic and thermophysical properties of the
Y_3-xEu_xSc₂Ga₃O₁₂ system have not been systematically studied.

Solid solutions of the Y_3-xEu_xSc₂Ga₃O₁₂ system (0<x<3) were synthesized by a high-temperature solid-state reaction at 1793 K using B₂O₃ as a flux. The phase purity of the obtained samples was verified by XRD using a Bruker D8 diffractometer with a VANTEC -1 linear detector and CuKα radiation. The synthesized garnets belong to the cubic space group $Ia\overline{3}d$.

The temperature dependence of the heat capacity for all obtained substances was determined by differential scanning calorimetry (DSC) using a STA 449 S Jupiter instrument. The experiments were conducted in platinum crucibles with lids, with a heating rate of 20 K/min, from 323 K to 1023 K in an air atmosphere. The obtained results are presented in the figure.

Dependence of the specific heat capacity on the composition of Y_3-xEu_xSc₂Ga₃O₁₂:
1 – Т = 323 К, 2 – Т = 523 К, 3 – Т = 723 К, 4 – Т = 923 К

Substitution of Y³⁺ ions with Eu³⁺ ions leads to a nonlinear decrease in heat capacity in the Y_3-xEu_xSc₂Ga₃O₁₂ system throughout the studied temperature range.

The work was carried out within the framework of the state assignment of the Ministry of Science and Higher Education of the Russian Federation for science of the Siberian Federal University, project FSRZ-2026-0011.