EN
The crystallochemical characteristics of polycrystalline samples, Sr_{1-x}La_{x}AlO_{4}, Sr_{1-x}Νd_{x}ΑlO_{4} (x = 0.02+0.20) and Sr_{1-x}Bi_{x}NdΑlO_{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_{4}, SrLaGaO_{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.