Influence of ceramic process and Eu content on the composite multiferroic properties of the Ba6−2xLn2xFe1+xNb9−xO30 TTB system

The present work reports the optimisation of the composition and elaboration process of Ba_6−2xLn_2xFe_1+xNb_9−xO₃₀ (0.6 < x < 1.0), a composite multiferroic below 440 K. Both firing and sintering conditions have been investigated in order to lower the two spurious phases content and to improve the ceramic quality. The Eu content has also been varied, with subsequent adjustment of cationic content to maintain charge compensation and site occupancies. The evolution of phase content, dielectric and magnetic properties has been evaluated with respect to these parameters. It was found that optimal processing parameters allow a significant improvement of dielectric properties but leave magnetic properties unaffected. Eu content modification impacts both the dielectric and magnetic properties of the TTB samples and changes their dielectric behaviour from ferroelectric to relaxor.