Eur. Phys. J. Appl. Phys.
Volume 55, Number 2, August 2011
|Number of page(s)||11|
|Section||Physics of Energy Transfer, Conversion and Storage|
|Published online||11 August 2011|
Electrical and electromechanical studies in ferroelectric Gd3+ modified lead potassium niobate ceramics
Centre for Piezoelectric Transducer Materials, Department of Physics, Andhra University, Visakhapatnam, 530 003, India
2 Department of Physics, GVP College of Engineering, Visakhapatnam, India
3 Department of Physics, GITAM Institute of Technology, GITAM University, Visakhapatnam, India
4 Department of Inorganic Materials Engineering, Kyung Pook National University, Daegu 702701, Republic of Korea
a e-mail: firstname.lastname@example.org
Revised: 7 February 2011
Accepted: 19 April 2011
Published online: 11 August 2011
The change in dielectric constant relaxation time over temperature (35–590 °C) and frequency (45 Hz–5 MHz) in ceramics of Pb0.77K0.115Gd0.115Nb2O6 (PKGN, Tc = 340 °c) has been studied. Powder X-ray diffraction revealed the single-phase formation with orthorhombic crystal structure. The P-E hysteresis loop parameters are Ps = 21.77 μC/cm2, Pr = 17.09 μC/cm2, Ec = 11.86 kV/cm; the piezoelectric constants, Kp = 31.7%, Kt = 47%, d33 = 115 × 10−12 C/N, d31 = −41 × 10−12 C/N, are determined in the material and some transducer applications are discussed. Cole-Cole (Zll vs. Zl) plots showed a non-Debye type relaxation. Conductivity obeyed Jonscher’s universal power law, σ = σ0 + Aωn. The theoretical values of εl and σ are computed using the parameters ‘A(T)’ and ‘n(T)’ (0 < n < 1) and are well fitted with the experimental data. The hopping ion frequency (ωp) and charge carrier concentration (Kl) have been analyzed using Almond-West formalism. The dielectric relaxation processes are associated with localized oxygen vacancies conduction at high frequency region. A long-range conductivity by Gd3+ ions is found to be predominant at low frequency region. The activation energies from impedance and modulus formalisms revealed the ionic type conduction in PKGN.
© EDP Sciences, 2011
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