Anisotropic colossal dielectric response of 0.93Pb(Fe1/2Nb1/2)O3–0.07PbTiO3 single crystals along [100] and [111] directions

Abstract

The temperature, frequency, and voltage dependences of the dielectric properties of 0.93Pb(Fe1/2Nb1/2)O3-0. 07PbTiO3 single crystals were investigated in the temperature range of 100-300K. An anisotropic colossal dielectric response was observed when the probe of the AC field was along the [100] and [111] directions. One relaxation was detected in the [100] direction, while two relaxations were detected in the [111] direction. The activation energies of the relaxations are in the range of 0.155-0.190eV, indicating that the relaxations are probably caused by 3d electrons hopping between Fe2+ and Fe3+. The origin of the anisotropic colossal dielectric response can be explained by a "two-hopping path" model. © 2011 The Japan Society of Applied Physics.