Experiments on growth of (SrAl0.5Ta0.5O3)(1-x)(LaAlO3)(x) perovskite crystals by the Czochralski and floating zone methods in whole composition range are reported. The structure of these crystals was investigated by precise X-ray measurements at room and elevated temperatures. The experiments allowed us to propose a schematic phase diagram of this solution; solid solutions exist at a concentration of 0 less than or equal to x less than or equal to 0.5 when crystals assume a cubic structure. The Czochralski method may be used to grow single crystals with a composition x = 0.23-0.41. Neither any structural phase transition nor tendency to form twins was detected in these solid solution crystals. The lattice parameters, thermal expansion coefficient and high melting point close to 1850degreesC indicate their high thermal and chemical stability and prove that these crystals may be used as substrates for high-temperature superconductor, manganites or GaN epitaxial layers. (C) 2003 Elsevier B.V. All rights reserved.