Solid State Communications 150 (2010) 1245–1248 Contents lists available at ScienceDirect Solid State Communications journal homepage: www.elsevier.com/locate/ssc Structural and relaxor behavior of Ba[Zr x Ti 1−x−y ](Zn 1/3 Nb 2/3 ) y O 3 ceramics obtained by a solid-state reaction A. Aoujgal a,d , H. Ahamdane b , M.P.F. Graça c , L.C. Costa c , A. Tachafine d , J.C. Carru d , A. Outzourhit a,∗ a Laboratoire de Physique du Solide et des Couches Minces, Faculté des Sciences Semlalia, Université Cadi Ayyad, Bd Pr. My. Abdellah, B.P. 2390, 40000 Marrakech, Maroc b Laboratoire Sciences des Matériaux, Faculté des Sciences Semlalia, Université Cadi Ayyad, Marrakech, Maroc c I3N and Physics Department, University of Aveiro, Campus Universitário de Santiago 3810-193 Aveiro, Portugal d Laboratoire d’Etude des Matériaux et des Composants pour l’Électronique (LEMCEL) Université du Littoral - Côte d’Opale, 50 rue Ferdinand Buisson, B.P. 717, 62228 Calais, France article info Article history: Received 4 November 2009 Received in revised form 22 March 2010 Accepted 31 March 2010 by J. Fontcuberta Available online 22 April 2010 Keywords: A. Relaxor ferroelectric A. BZT ceramics D. Vogel–Fulcher E. Dielectric properties abstract Ba[Zr x Ti 1−x−y ](Zn 1/3 Nb 2/3 ) y O 3 (BZT–ZN) ceramics (x = 0.1) were prepared by the solid-state reaction route and their structural and dielectric properties were investigated. It was found at room temperature that the ceramics with y = 0, 0.05 and 0.1 present perovskite-type cubic structure. The temperature and frequency dependence of the dielectric constant was investigated in the temperature range from 80 to 400 K and for frequencies ranging from 0.1 to 500 kHz. It was observed that when y increases from 0 to 0.1, the transition temperature decreases and the degree of diffuseness of the phase transition increases. For y = 0.1, a clear relaxor behavior was noted. In this case, the dielectric relaxation rate followed de Vogel–Fulcher relation with an activation energy of E a = 0.1 eV, an attempt frequency F 0 = 2 × 10 14 Hz and a static freezing temperature T VF = 122 K. The results are discussed in terms of existing models. © 2010 Elsevier Ltd. All rights reserved. 1. Introduction Ferroelectric materials of perovskite-class and formula (ABO 3 ) have received considerable attention in electromechanical, elec- tronic and microwave applications [1,2]. In particular, there is a re- newed interest in the environmental friendly lead-free perovskite Ba(Zr x Ti 1−x )O 3 (BZT) as a substitute for Ba 1−x Sr x TiO 3 (BST) in these applications due to its high dielectric constant, relatively low di- electric losses, large voltage tunability of the dielectric constant, as well as a good chemical stability [3–5]. Depending on the value of x, this material can exhibit either a normal ferroelectric or relaxor behavior [6]. Indeed, a normal ferroelectric behavior was observed for compositions 0 ≤ x ≤ 0.1, followed by an increase in the de- gree of diffuseness of the ferroelectric to paraelectric transition for 0.1 ≤ x ≤ 0.25 [7–9] and a relaxor behavior for x ≥ 0.25 [10]. The relaxor state is characterized by a strong dispersion of the dielec- tric constant for temperatures below the maximum permittivity temperature T m , by a shift of T m towards higher values when the frequency is increased and by a deviation from the Curie–Weiss law in the paraelectric phase around T m [11]. In addition, zirconium substitution of Ti reduces the transition temperature [11–13]. ∗ Corresponding author. Fax: +212 5 24 43 74 10. E-mail addresses: aoutzour@ucam.ac.ma, aoutzour@gmail.com (A. Outzourhit). The relaxor behavior can also be induced by the substitution of the B cation sites in BaTiO 3 by hetrovalent ions. This is, for example, the case of the study reported recently on BaTi 1−y (Zn 1/3 Nb 2/3 ) y O 3 , which showed relaxor-type properties for y = 0.1 and y = 0.95 [14]. Other studies have focussed on the effect of doping on the dielectric properties the ferroelectric relaxor BZT [15–17]. Since BZT behaves as a normal ferroelectric when x ≤ 0.1, it would be interesting to investigate the effect of heterovalent substitution of Ti 4+ in this system. The overall objective of this in- vestigation is to obtain new lead-free and consequently environ- mentally friendly relaxor materials with improved properties for electronic and microwave applications. Therefore, in the present work we report on the structural and the relaxor behavior of Ba[Zr x Ti 1−x−y ](Zn 1/3 Nb 2/3 ) y O 3 (x = 0.1) system, obtained by the substitution of titanium by Nb and Zn in BaZr x Ti 1−x O 3 (x = 0.1). The value of x was chosen to be below the threshold value for the onset of relaxor behavior in BaZr x Ti 1−x O 3 . 2. Material and methods Ceramic samples with the chemical formula Ba[Zr x Ti 1−x−y ] (Zn 1/3 Nb 2/3 ) y O 3 with x = 0.1, y = 0, 0.025, 0.05, 0.075 and 0.1 (referred to as BZT–ZN) were prepared by the conventional solid-state reaction method [18], using stochiometric proportions of high purity powders of barium carbonate (BaCO 3 ) (Fluka, 99%) 0038-1098/$ – see front matter © 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.ssc.2010.03.035