Isovalence Substitutions in Multicomponent Aluminates ABCO$\text{}_{4}$

The crystallochemical characteristics of polycrystalline samples, Sr$\text{}_{1-x}$La$\text{}_{x}$AlO$\text{}_{4}$, Sr$\text{}_{1-x}$Νd$\text{}_{x}$ΑlO$\text{}_{4}$ (x = 0.02+0.20) and Sr$\text{}_{1-x}$Bi$\text{}_{x}$NdΑlO$\text{}_{4}$ (x = 0.05 ÷ 0.50) prepared by the oxalate coprecipitation and cryochemical technique have been investigated. The existence limits of single-phase states for pairs of elements Sr-Pb (x < 0.05) and Nd-Bi (x < 0.2) were determined. The microprobe X-ray analysis showed the Bi uniform distribution. The dielectric properties of pure SrLaΑlO$\text{}_{4}$, SrLaGaO$\text{}_{4}$ and partial replacement La → Nd samples were measured. It can be concluded that these compounds are suitable as substrate materials of HTSC thin films.