Ferroelectric solid solutions with perovskite- and columbite-type components: From structures formation to domain and hysteresis phenomena

The paper reports results on the complex study on ferroelectric ceramics that represent solid solutions containing components with a perovskite-type or columbite-type structure.Solid solutions of a three-component(1−x−y)NaNbO_(3)−xKNbO_(3)−yCdNb_(2)O_(6) system are manufactured at x=0.05-0.20 and y=0.10.Domain structures in ceramic grains are studied.The consistency between experimental and calculated results is examined for coexisting phases split into non-180°domains(mechanical twins)in the solid solution with x=0.15.A correlation between the internal structure(crystal,domain,granular,and defect)and fundamental elec­tromechanical and polarization properties is stated for the studied three-component solid solutions.

Binary perovskite solid solutions and trends in their phase transitions temperatures variation

Some of the known binary ABO_(3)perovskites with ferro-(FE)or antiferroelectric(AFE)at T_(C)and different magnetic phase tran-sitions(PT):ferro-and antiferromagnetic at T_(N)and also some of their solid solutions are considered.Some correlations between their FE or AFE and/or magnetic PTs temperatures,on the one hand,and their interatomic bond A-O strains,on the other hand,have been constructed.It is shown that in the plotted diagrams these temperatures change with a change inδAO values as follows:classical FEs are followed by multiferroics,starting with BiFeO_(3)and ending with YVO_(3),followed by classical AFEs.At the same time,the temperatures T_(C)and T_(N)experience maxima at the corresponding points for BiFeO_(3),then quickly decrease,and the difference between them,T_(C)-T_(N),basically also decreases,slightly increasing along the way to the point EuTiO_(3).which made it possible to systematize these T_(C)and T_(N).