Influence of Space Charge Layers on the Dielectric Properties of Ba_0.6Sr_0.4TiO₃Nanostructured Thin Films

Abstract

Barium strontium titanate (Ba 0.6 Sr 0.4 TiO 3 ) nanostructured thin films have been deposited on platinized silicon substrates by the sol-gel method. The as-fired films were found to be amorphous, which crystallize to cubic phase after annealing at 550 • C in air for one hour. The low-frequency dielectric responses of the BST films were measured as functions of frequency range from 1 kHz to 1MHz. The thickness dependence dielectric constant of the BST thin films were measured in the temperature range from −150 • C to 150 • C at 100 kHz and discussed in the light of an interfacial dead layer. All the samples showed a diffuse type phase transitions. Both the dielectric constant and loss tangent showed anomaly peaks at about 10 • C, which corresponds to a tetragonal ferroelectric-to-cubic paraelectric phase transition.

Effects of Ba2+/Sr2+ ratio on the microstructure, dielectric and ferroelectric properties of BaxSr(1−x)TiO3 films prepared by micro-arc oxidation

“…The dielectric constants of all BST films drop with increasing frequency in general. According to the literature [33][34][35], the fall in dielectric constants might arise from the fact that the polarization does not occur instantaneously with the application of the electric field because of inertia. The loss and fall in dielectric constant values may occur as a result of the delay in reaction to the applied alternating electric field.…”

Investigation of fatigue behavior of Pb(Zr0.45Ti0.55)O3 thin films under asymmetric polarization switching

“…Although alternative materials with improved fatigue endurance are developed for its use in memories, PZT still attracts our research interest because of its unique ferroelectric property. During the past twenty years, a number of fatigue mechanisms have been proposed, including the charge injection of electrons from the cathode, [1][2][3][4][5] the formation of a chemically distinct damaged "dead" layer, [6][7][8][9][10] domain pinning by charged defect centers, and the formation of space-charge layers near the ferroelectric-electrode interfaces. [11][12][13][14][15] Ionic defects such as the oxygen vacancy (V O •• ) are considered in many fatigue mechanisms.…”