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Relaxor properties of Ba(Zr,Ti)O3 ceramics

C. E. CIOMAGA1,* , R. CALDERONE2, M. T. BUSCAGLIA3, M. VIVIANI3, V. BUSCAGLIA3, L. MITOSERIU1,2, A. STANCU1, P. NANNI2

Affiliation

  1. Dept. of Solid State and Theoretical Physics, Al. I. Cuza University, Blvd. Carol I, 11, Iasi 700506, Romania
  2. Dept. of Chemical Processes, University of Genoa, P.le Kennedy 1, I-16129 Genoa, Italy
  3. Institute of Energetics and Interphases – CNR, Via De Marini 6, I-16149 Genoa, Italy

Abstract

BaZrxTi1-xO3 is a possible candidate as environmental friendly electroceramic material (Pb-free ferroelectric) due to its high dielectric and piezoelectric constants and ferroelectric properties in a temperature range which can be tuned by the composition. Its properties change from full ferroelectric behavior (x=0; BaTiO3) with a sharp ferro-para phase transition to the full relaxor state (for 0.10≤x≤0.35), when the structure is pseudo-cubic and the transition has a strong diffuse character and a frequency-relaxation in the kHz range. In the present work, the cross-over composition BaZr0.1Ti0.9O3 was investigated. The ceramics have been prepared via solid state reaction; optimum parameters for calcination and sintering in order to obtain pure perovskite phase and a good densification have been found. The temperature dependence of the dielectric constant shows a diffuse phase transition with a small shift of the temperature corresponding to the maximum permittivity of (1-2) oC in the frequency range of 1 Hz÷1 MHz. The losses are smaller than 30% for temperatures below 130 oC, with a slight increasing at low frequency and high temperatures. The real part of the permittivity follows the Curie Weiss law with frequency-dependent constants. The dielectric spectroscopy data show at least two relaxation processes: a thermally-activated one characteristic to low-frequency range f<100 Hz and a temperature-independent one at f≥100 Hz..

Keywords

BaTiO3 solid solution, Ferroelectric relaxor, Lead-free ceramics.

Submitted at: March 15, 2006
Accepted at: May 18, 2006

Citation

C. E. CIOMAGA, R. CALDERONE, M. T. BUSCAGLIA, M. VIVIANI, V. BUSCAGLIA, L. MITOSERIU, A. STANCU, P. NANNI, Relaxor properties of Ba(Zr,Ti)O3 ceramics, Journal of Optoelectronics and Advanced Materials Vol. 8, Iss. 3, pp. 944-948 (2006)