title: Quest for lead free relaxors in YIn(1-x)Fe(x)O₃ (0.0 ≤ x ≤ 1.0) system: role of synthesis and structure.
abstract: The B-site tailored YIn(1-x)Fe(x)O3 (0.0≤ x≤ 1.0) series was synthesized by glycine-aided gel-combustion technique and subjected to extensive structural and electrical investigations. The temperature had tremendous bearing on the phase evolution exhibited by the system. The entire system crystallized as C-type metastable polymorph in the as-synthesized form. Hexagonal polymorphs of Fe(3+)-rich compositions could be isolated by controlled heat treatment at 750 °C. Raman spectroscopic investigations showed that, while there is a general shrinkage of the lattice due to substitution of a smaller ion at In(3+)-site, there is an apparent dilation of the Y-O bond, and this anomaly reflects in the electrical behavior exhibited by the system. The single-phasic hexagonal nominal compositions, YIn(1-x)Fe(x)O3 (0.0 ≤ x ≤ 0.3), were also studied by impedance spectroscopy. The dielectric constant was found to drastically increase from 10 for YInO3 to 1000 for YIn(0.7)Fe(0.3)O3 at room temperature stressing the role of B-site tailoring on electrical behavior. More interestingly, careful substitution of Fe into YInO3 could tune the electrical behavior from a dielectric to relaxor ferroelectric in the temperature range studied. The nominal composition YIn(0.7)Fe(0.3)O3 showed a classical relaxor ferroelectric like behavior which is an important observation in context of the search for new lead free relaxor materials.
authors.affiliation: Chemistry Division, ‡UGC-DAE Consortium for Scientific Research, and §Radiation and Photochemistry Division, Bhabha Atomic Research Centre , Mumbai 400085, India.
authors.forename: Rakesh
authors.initials: R
authors.lastname: Shukla
authors.forename: Farheen N
authors.initials: FN
authors.lastname: Sayed
authors.forename: Vinita
authors.initials: V
authors.lastname: Grover
authors.forename: Sudhanshu K
authors.initials: SK
authors.lastname: Deshpande
authors.forename: Apurav
authors.initials: A
authors.lastname: Guleria
authors.forename: Avesh K
authors.initials: AK
authors.lastname: Tyagi