title: Structural manipulation and tailoring of dielectric properties in SrTi1-xFexTaxO3 perovskites: Design of new lead free relaxors.
abstract: We report composition dependent structure evolution from SrTiO3 to SrFe0.5Ta0.5O3 by powder X-ray and neutron diffraction studies of SrTi1-2xFexTaxO3 (0.00 ≤ × ≤ 0.50) compositions. Structural studies reveal cubic (Pm3m) perovskite-type structure of the parent SrTiO3 for x up to 0.075 and cation disordered orthorhombic (Pbnm) perovskite-type structure for x ≥ 0.33. A biphasic region consisting of a mixture of cubic and orthorhombic structures is found in the range for 0.10 ≤ × ≤ 0.25. Dielectric studies reveal transformation from a normal dielectric to relaxor like properties with increasing Fe(3+) and Ta(5+) concentration. Dielectric response is maximum at x = 0.33 in the series. The results establish a protocol for designing new lead-free relaxor materials based on the co-substitution of Fe(3+) and Ta(5+) for Ti(4+) in SrTiO3. A complex interplay of strain effects arising from distribution of cations at the octahedral sites of the perovskite structure controls the dielectric properties.
authors: Chemistry Division, Bhabha Atomic Research Centre, Mumbai-400085, India.
authors: R
authors: R
authors: Shukla
authors: Chemistry Division, Bhabha Atomic Research Centre, Mumbai-400085, India.
authors: S J
authors: SJ
authors: Patwe
authors: UGC-DAE Consortium for Scientific Research, Bhabha Atomic Research Centre, Mumbai-400085, India.
authors: S K
authors: SK
authors: Deshpande
authors: Chemistry Division, Bhabha Atomic Research Centre, Mumbai-400085, India.
authors: S N
authors: SN
authors: Achary
authors: Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085, India.
authors: P S R
authors: PS
authors: Krishna
authors: Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085, India.
authors: A B
authors: AB
authors: Shinde
authors: Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore-560 012 India.
authors: J
authors: J
authors: Gopalakrishnan
authors: Chemistry Division, Bhabha Atomic Research Centre, Mumbai-400085, India.
authors: A K
authors: AK
authors: Tyagi