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Abstract: (K,Na)NbO3 ferroelectric films were grown on LaNiO3 coated silicon substrates by RF magnetron sputtering. The conductive LaNiO3 films acted as seed layers and induced the highly (001) oriented perovskite (K,Na)NbO3 films. Such films exhibit saturated hysteresis loops and have a remnant polarization (2P r) of 23μC/cm2, and coercive field (2E c) of 139kV/cm. The films showed a fatigue-free behavior up to 109 switching cycles. A high tunability of 65.7% (@300kV/cm) was obtained in the films. The leakage current density of the films is about 6.0×10−8 A/cm2 at an electric field of 50kV/cm. [Copyright &y& Elsevier]

It has been reported that grain size has significant influence on the dielectric properties of barium strontium titanate (BST) thin films. In this paper we have proposed a multilayer structure in which BST layers are separated by thin MgO layers which are expected to function as barrier to atomic diffusion so that the grain size of BST could be confined. By simulation we have found that for a device with a coplanar/composite film/substrate configuration, the introduction of MgO can effectively change the dielectric constant of the composite while the tunability is not significantly affected, provided the amount of MgO is smaller than 25%. A prototype device was prepared to demonstrate the feasibility of this idea. By X-ray diffraction measurements it is revealed that BST and MgO coexist in the composite. The dielectric property of the composite film was determined and it was found that the film has a tunability of up to ~7% at 500 MHz and under an electric field of 13.3 kV/mm. [ABSTRACT FROM AUTHOR]

SrRuO 3 (SRO) thin films were grown on SiO 2 /Si substrates with different thickness of LaNiO 3 (LNO) seed layers by RF magnetron sputtering. Effects of LNO thickness on the grain orientation, surface morphology, magnetic behavior and electrical transport properties of SRO films were investigated. The orientation of SRO films transformed from (110) pc to (001) pc and the residual stress was released gradually with increasing the thickness (pc refers to the pseudo-cubic unit cell of SrRuO 3 ). SRO films with higher orientation grown on LNO exhibited more flat surface, higher saturation magnetization, and lower coercive field. The magnetic anisotropy was enhanced on thicker LNO due to the different states of residual stress. In addition, the temperature dependence of resistivity was promoted by the microstructural disorder. (110) pc -oriented SRO monolayer electrode and (001) pc -oriented SRO/LNO300 bilayer electrode own low room temperature sheet resistance of 0.38 Ω/□ and 0.26 Ω/□, respectively. The results indicate that the controllable SRO films can be used as not only good bottom electrodes but also promising templates to control the crystallographic orientations of various other perovskite-based functional materials. [ABSTRACT FROM AUTHOR]

Abstract: We report the fabrication of Pb0.4Sr0.6TiO3 thin films with different microstructures and dielectric responses deposited on LaNiO3 buffered silicon substrate via the RF magnetron sputtering method with various deposition powers from 40W to 120W. Effects of the power on deposition rate, orientation, surface morphology and dielectric response were investigated. X-ray diffraction patterns indicated that the crystal orientation of thin films changes from (110) preferential orientation to random orientation with decreasing power, and finally to perfect (100) orientation. Moreover, the thin films prepared at lower power show more homogeneous grain size distribution and denser microstructure. The capacitance–voltage analysis revealed that the films deposited at lower powers show larger dielectric response and better tunability performance. Especially, large dielectric constant and tunability of 947 and 80.88% (@400kV/cm), respectively, were obtained under a deposition power of 40W. [Copyright &y& Elsevier]

La 0.7 Ca 0.3− x Sr x MnO 3 ( x =0, 0.10, 0.15, 0.25 and 0.30) thin films were prepared by the sol–gel method on Si substrates. The structural, magnetic and transport properties were systematically studied. All the LCSMO thin films crystallized perfectly with a random crystalline orientation. The films show strong coupling between lattice and physical properties. With the increment in x , the lattice parameter increases, the magnetic properties are enhanced, and the T c increases monotonically from 235 K to 343 K. Resistivity is dramatically decreased with Sr dopant. The temperature corresponding to the MR maxmium value is close to that of the T MI for LCMO, while there was no peak value for Sr doped thin films in this temperature range. [ABSTRACT FROM AUTHOR]