Titanium doped yttrium manganite: improvement of microstructural properties and peculiarities of multiferroic properties.

Yttrium manganite, YMnO₃, was doped with different concentrations of titanium (x = 0, 0.04, 0.08, 0.10, 0.15, 0.20) in order to improve the microstructural and multiferroic properties. The powders were prepared using sol-gel polymerization complex method from citrate precursors. Depending on the titanium concentration, the hexagonal structure and/or the rhombohedral superstructure are present in the sintered samples. The YMn_1–xTi_xO_3+δ (x = 0.10, 0.15, 0.20) ceramic samples showed significantly reduced density of microcracks, and of inter- and intragranular pores, and relative densities greater than 90%. The structural parameters for YMn_1–xTi_xO_3+δ (x = 0, 0.10, 0.15) were correlated with the results of magnetic and ferroelectric measurements. The most of titanium-doped samples showed a reduction of the leakage current density in comparison with undoped YMnO₃, and their ferroelectric responses were slightly improved. The modifications in structural arrangement resulted in partial suppression of ideal antiferromagnetic ordering visible through decrease of the Néel temperature and Weiss parameter, as well as the appearance of weak ferromagnetism and increase of magnetization (especially, in samples x = 0.08, 0.10, 0.15). These changes in physical quantities most likely originated from incorporation of the uncompensated magnetic moments and possible spin canting induced by enhanced symmetry break of the superexchange bridges. Highlights: Synthesis of YMn_1−xTi_xO_3+δ (x = 0–0.20) powders using sol-gel polymerization complex method. Synthesis method and doping reduced microdefects and increased ceramics' relative density. The leakage currents decreased in YMn_1−xTi_xO_3+δ ceramics upon doping. Reduction in geometrical frustration of antiferromagnetic structure after Ti-doping. Enhanced weak ferromagnetic response in YMn_1−xTi_xO_3+δ (x = 0.10, 0.15, 0.08) samples. [ABSTRACT FROM AUTHOR]