Linear Versus Nonlinear Field Dependence of Dielectric Stiffness in Relaxors

Abstract

Dielectric permittivity studies in the field-cooled mode show a linear dependence of dielectric stiffness (inverse dielectric permittivity) on dc bias in PbMg_1/3Nb_2/3O₃–PbTiO₃ crystals and some other relaxors above a certain threshold bias value. The observed behavior can be described by extrinsic contributions like 90°-domain wall movements and/or rotations of dipole moments (polarization-rotation).

Keywords:

• Dielectric permittivity
• dielectric stiffness
• nonlinearity
• relaxors

PACS:

• 63.50.+x
• 77.22.Ch
• 77.84.Dy