Tantalum pentoxide (Ta2O5) is promising for coating and piezoelectric applications and has been considered as the dielectric gate material for the next generation of memory devices. In this work, TiO2-doped Ta2O5 crystals were prepared using the laser-heated pedestal growth technique, as grown specimens were found to crystallize in monoclinic phase at room temperature. The structural modifications in these crystals resulting from variation of TiO2 composition (0-11%) and temperature (-248-900 degreesC) were studied using Raman spectroscopy. The low frequency external modes (upsilon < 100 cm(-1)) that originate from the interaction between TaOn5-2 eta/Ta6O12+6 clusters/polyhedra exhibit a strong compositional and temperature dependence in terms of their intensity and frequency variations. The Raman spectral evolutions suggested a monoclinic to orthorhombic structural phase transition at about 327, 397, 487, and 577 degreesC For 0, 5, 8, and 11% TiO2-doped Ta2O5, respectively. (C) 2001 Elsevier Science Ltd. All lights reserved.