Anisotropic Colossal Dielectric Response of 0.93Pb(Fe_1/2Nb_1/2)O₃–0.07PbTiO₃ Single Crystals along [100] and [111] Directions

Abstract

The temperature, frequency, and voltage dependences of the dielectric properties of 0.93Pb(Fe 1=2 Nb 1=2 )O 3 -0.07PbTiO 3 single crystals were investigated in the temperature range of 100-300 K. 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 0.155-0.190 eV, indicating that the relaxations are probably caused by 3d electrons hopping between Fe 2þ and Fe 3þ . The origin of the anisotropic colossal dielectric response can be explained by a ''two-hopping path'' model.

Structures and Dielectric Properties of Pb(Fe1/2Nb1/2)1-xTixO3Single Crystals

“…Our last work was focused on the anisotropic dielectric properties of PFNT (x ¼ 0:07) single crystals along the [100] and [111] directions. 13) However, in this study, we focus on the structures and dielectric anomalies of the PFNT (x ¼ 0:07, 0.48) single crystals in the temperature range of 90-300 K. Two dielectric anomalies were observed in the sample PFNT (x ¼ 0:07) while only one was detected in PFNT (x ¼ 0:48). The origins of the dielectric anomalies were discussed on the basis of the obtained X-ray diffraction (XRD), Raman, and X-ray absorption fine structure (XAFS) spectra.…”