Dielectric properties of BaTiO3/SrTiO3 multilayered thin films prepared by pulsed laser deposition

Abstract

BaTiO 3 /SrTiO 3 multilayered thin films were deposited on Si and Pt/Si substrates. X-ray diffraction clearly shows the formation of the superstructures. Phase transition properties were studied via dielectric measurements. Glassy behavior, characterized by a strong frequency dispersion of dielectric properties, was found in samples with a total thickness of 400 nm, while in samples with a total thickness of 800 nm, normal ferroelectric phase transitions with two dielectric peaks were observed. A preliminary interpretation assumes that size effects which frustrate long range ferroelectric ordering may lead to the relaxational behavior in BaTiO3/SrTiO3 superstructures.

Dielectric properties of ferroelectric thin films with surface transition layers

“…Using mean field approximation and assuming that the pseudo-spins in the same layer have the same values, the spin average along the z direction in the i th layer can be expressed by: (4) where is the mean field acting on the i th spin, , k B is the Boltzmann constant. The spontaneous polarization P s is proportional to Let R m denotes the value of in the m th layer, then (5) where…”

“…However, surface and size effects are two important phenomena observed in ferroelectric thin films which have been known since early 1950's and still have many problems to be answered. In recent years the finite-size and surface effects on the phase transition temperature, spontaneous polarization, and dielectric susceptibility of ferroelectric thin films have been extensively studied both experimentally [1][2][3][4] and theoretically [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. The Dielectric properties have been reported for Pb(Zr, Ti) O 3 (PZT) [21,22], PbTiO 3 [23], BaTiO 3 [24], and (Ba, Sr)TiO 3 (BST) [25,26] thin films by many groups.…”

Особенности Сегнетоэлектрического Состояния В Двухслойных Гетероструктурах На Основе Титаната Бария-Стронция

“…Сегнетоэлектрические гетероструктуры, состоящие из слоев различного состава (многослойные и сверхрешет-ки), сформированные на диэлектрических подложках, интенсивно исследуются [1][2][3] с целью повышения ди-электрической проницаемости [4] и ее термостабильно-сти, понижения диэлектрических потерь и увеличения диэлектрической нелинейности под действием внешне-го электрического поля для задач сверхвысокочастот-ной микроэлектроники [5][6][7][8]. Исследования направлены на поиски новых путей управления свойствами гете-роструктур за счет деформации элементарной ячей-ки в тонкой пленке и интерфейсного влияния [5,6].…”

Epitaxial Integration of Ferroelectric BaTiO3 with Semiconductor Si: From a Structure- Property Correlation Point of View

“…18(a) and (b): (1) A broadened maximum in the dielectric constant appears at a wide temperature ranging from 80 °C to 120 °C, (b) the magnitude of the dielectric constant decreases, while T c increases with increasing frequency, (c) the peak in dielectric loss is also frequency dependent and it shifts to higher temperatures with increasing frequency. The above observed strongly frequency dependent dielectric properties resemble the typical diffusive ferroelectric phase transition in ferroelectric relaxors rather than a normal ferroelectric phase transition, which shows a sharp anomaly at the T c [89]. According to Smolensky and Uchino et al [90,91], the diffuseness of the phase transition can be investigated by a modified Curie-Weiss (CW) law,…”