Cluster and domain-wall dynamics of ferroelectric Sr1-xCaxTiO3.

摘要: The dielectric permittivity of the xy-type random-field system ${\mathrm{Sr}}_{0.942}$${\mathrm{Ca}}_{0.058}$${\mathrm{TiO}}_{3}$ is measured at frequencies 30${10}^{7}$ Hz and temperatures 7.5T200 K. At all a Debye-type, monodispersive process dominates with relaxation times \ensuremath{\tau}\ensuremath{\sim}${10}^{\mathrm{\ensuremath{-}}5}$ s. It attributed to off-center ${\mathrm{Ca}}^{2+}$ dipole dynamics, which also determines low-T ferroelectric bulk relaxation. T${T}_{c}$\ensuremath{\sim}35 K an additional polydispersive Cole-Cole--type domain wall observed. Its large spectrum centered around \ensuremath{\tau}\ensuremath{\sim}${10}^{\mathrm{\ensuremath{-}}3}$ s gives rise glasslike behavior low T. Experiments external electric fields competing built-in random are discussed.