Physics – Condensed Matter – Materials Science
Scientific paper
2002-07-19
Phys. Rev. B 66, 0641xxx (August 01, 2002)
Physics
Condensed Matter
Materials Science
PDF file. 14 pages, 9 figures collected on pp.11-13
Scientific paper
10.1103/PhysRevB.66.064103
The dielectric permittivity e at frequencies from [10^(-1) -10^(-5)] Hz to 10^5 Hz is studied in perovskite (1-x)Pb(Mg1/3Nb2/3)O3 - xPbTiO3 relaxor ferroelectric ceramics of different compositions x = 0.35, 0.25 and 0, which exhibit, below the temperature of the diffuse epsilon'(T) maximum Tm, a tetragonal ferroelectric, a rhombohedral ferroelectric and a nonergodic relaxor phase, respectively. The universal relaxor dispersion previously observed at temperatures near and above Tm in the ceramics of x=0.25, is also found to exist in other compositions. This dispersion is described by the fractional power dependence of the real and imaginary parts of susceptibility on frequency. The real part of the universal relaxor susceptibility chi'U is only a comparatively small fraction of the total permittivity epsilon', but chi"U is the dominant contribution to the losses in a wide frequency-temperature range above Tm. In the high-temperature phase a quadratic divergent temperature behavior is observed for all the three compositions studied. The universal relaxor susceptibility is attributed to the polarization of polar nanoregions, which are inherent in the relaxor ferroelectrics. A microscopic model of this polarization is proposed, according to which the dipole moments of some ('free') unit cells inside polar nanoregion can freely choose several different directions, while the direction of the total moment of the nanoregion remains the same. The ensemble of interacting polar nanoregions is described in terms of a standard spherical model, which predicts the quadratic divergence of susceptibility above the critical temperature, in agreement with the experimental results.
Bokov Alexei A.
Ye Zuo-Guang
No associations
LandOfFree
Universal relaxor polarization in Pb(Mg1/3Nb2/3)O3 and related materials does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Universal relaxor polarization in Pb(Mg1/3Nb2/3)O3 and related materials, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Universal relaxor polarization in Pb(Mg1/3Nb2/3)O3 and related materials will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-541079