Synthesis of Gd+3 doped hydroxyapatite ceramics: optical, thermal and electrical properties.

In this study, hydroxyapatite powder Ca₁₀(PO₄)₆(OH)₂ (HAp) doped with gadolinium (Gd³⁺) (HAp:Gd³⁺) in different mole percentage of between 0.1 and 1.6 was synthesized by sol−gel method at 900°C. The reaction was carried out by hydrolysis of Ca(OH)₂ and DCPD (CaHPO₄.2H₂O) in aqueous solution and then analyzed through XRD, SEM, FTIR, TGA and Four-Point Probe method (custom-made). The results show that Gd³⁺ has been successfully doped into the hydroxyapatite structure. Then, the photoluminescence, thermal and electrical properties of pure and Gd³⁺ doped hydroxyapatite were studied and compared with the pure hydroxyapatite. In conclusion, the emission band of Ca_10-xGd_x(PO₄)₆(OH)₂ was observed at 263, 278, 294, 312 nm) under excitation with 185 nm. The Stokes shift of HAp:Gd³⁺ was calculated to be 16.031 cm⁻¹. On the other hand, the electrical and thermal conductivity of HAp increased with the increase in Gd³⁺ concentration due to Ca²⁺ cation vacancies caused by Gd³⁺doping. [ABSTRACT FROM AUTHOR]