title: Resolving the controversies about the 'nearly cubic' and other phases of Sr(1-x)Ca(x)TiO(3) (0≤x≤1): II. Comparison of phase transition behaviours for x = 0.40 and 0.43.
abstract: The phase transition behaviour of two 'nearly cubic' compositions, x = 0.40 and 0.43, of Sr(1-x)Ca(x)TiO(3), representative of Pbnm and Pbcm space group structures, has been investigated using temperature dependent dielectric, x-ray diffraction and Raman scattering techniques. For x = 0.40, a first order antiferroelectric phase transition occurs around 364 K followed by an antiferrodistortive phase transition involving the R point ([Formula: see text]) instability at ∼800 K. For x = 0.43, on the other hand, there is no antiferroelectric phase transition. Instead, two antiferrodistortive transitions around 463 and 850 K linked with the M ([Formula: see text]) and R ([Formula: see text]) point instabilities, respectively, are observed. Both the compositions also exhibit qualitatively different types of phase transitions below room temperature. Evidence for a new phase transition at low temperatures is presented for x = 0.43.
authors.affiliation: School of Materials Science and Technology, Institute of Technology, Banaras Hindu University, Varanasi-221005, India.
authors.forename: Sanjay Kumar
authors.initials: SK
authors.lastname: Mishra
authors.forename: Rajeev
authors.initials: R
authors.lastname: Ranjan
authors.forename: Dhananjai
authors.initials: D
authors.lastname: Pandey
authors.forename: Pierre
authors.initials: P
authors.lastname: Ranson
authors.forename: Robert
authors.initials: R
authors.lastname: Ouillon
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Pinan-Lucarre
authors.forename: Philippe
authors.initials: P
authors.lastname: Pruzan