From normal ferroelectric transition to relaxor behavior in Aurivillius ferroelectric ceramics Y. Gonza ´lez-Abreu • A. Pela ´iz-Barranco • J. D. S. Guerra • Y. Gagou • P. Saint-Gre ´goire Received: 8 April 2014 / Accepted: 4 July 2014 / Published online: 22 July 2014 Ó Springer Science+Business Media New York 2014 Abstract The inﬂuence of the barium concentration on the dielectric response of Sr 1-x Ba x Bi 2 Nb 2 O 9 system, with x = 0, 15, 30, 50, 70, 85, 100 at.%, has been studied. The barium concentration dependence of T m , as well as the temperature of the corresponding maximum for the real part of the dielectric permittivity, has suggested a cation site mixing among atomic positions, which has been sup- ported by the structural analysis. A transition from normal ferroelectric–paraelectric phase transition to a relaxor behavior has been observed in the studied samples, when the barium concentration has increased. The relaxor behavior has been discussed. Introduction Ferroelectrics materials of the Aurivillius family are mostly studied due to their potential technological [1–5]. The high spontaneous polarization, the fatigue-free behavior, and the low leakage currents of these materials make them prom- ising for applications in nonvolatile ferroelectric memories [6]. This group of materials possess a complex structure, which is composed of perovskite blocks ([A m Nb m O 3m?1 ] 2- ) interleaved between bismuth and oxygen layers ([Bi 2 O 2 ] 2? ), where m is the number of perovskite blocks in the structure [6–8]. The dodecahedral A site can be occu- pied by Bi 3? , Sr 2? , Ba 2? , Ca 2? , La 3? , Pb 2? ,K ? , etc. The octahedral B site is more size restrictive [9, 10] and is typically occupied by Ti 4? , Nb 5? , Ta 5? ,W 6? , Ga 3? , Al 3? , or Mn 3? . The number of perovskite blocks is related to the crystallographic orientation and to the plane of the polar- ization in these materials [11]. It has been discussed that the bismuth layers [Bi 2 O 2 ] 2? constrain the size of perov- skite blocks [9] establishing a limit for the incorporation of elements into them and providing the mixing of different elements between A sites and bismuth sites in the layered structure [9, 10]. The mixing of different elements into these sites determines the structural and dielectric proper- ties for these materials [1–10]. SrBi 2 Nb 2 O 9 ceramic material belongs to the Aurivillius family [10, 12–17]. Previous studies have shown a normal ferroelectric behavior in the ferroelectric–paraelectric phase transition [14–16]. Structural studies [17] on the bilayer system ABi 2 Nb 2 O 9 , with A = Sr 2? , Ca 2? , Ba 2? , have showed disordering between A sites and bismuth sites. The disorder increases with the ionic radii of the doping element. The dielectric studies [13] in Sr 1-x A x Bi 2 Nb 2 O 9 system, with A = Ca 2? , Ba 2? and 0 B x B 30 at.%, have showed a normal ferroelectric–paraelectric phase transition and a Y. Gonza ´lez-Abreu  A. Pela ´iz-Barranco (&) Facultad de Fı ´sica-Instituto de Ciencia y Tecnologı ´a de Materiales, Universidad de La Habana, San La ´zaro y L, 10400 Vedado. La Habana, Cuba e-mail: pelaiz@ﬁsica.uh.cu Y. Gonza ´lez-Abreu e-mail: yusling@ﬁsica.uh.cu J. D. S. Guerra Grupo de Ferroele ´tricos e Materiais Multifuncionais, Instituto de Fı ´sica, Universidade Federal de Uberla ˆndia, Uberla ˆndia, MG 38400-902, Brazil e-mail: santos@inﬁs.ufu.br Y. Gagou University of Picardie Jules Verne, LPMC, 80039 Amiens Cedex, France e-mail: yaogagou@gmail.com P. Saint-Gre ´goire Department of Sciences and Arts, University of Nı ˆmes, 30021 Nimes cedex 01; ICGM (UMR CNRS n° 5253), C2 M, 34095 Montpellier cedex 05, France e-mail: pstgregoire@gmail.com 123 J Mater Sci (2014) 49:7437–7444 DOI 10.1007/s10853-014-8448-0