Role of stress on the phase control and dielectric properties of (1-x) BiFeO3 - xBa0.5Sr0.5TiO3 solid solution thin films

2005 ◽  
Vol 875 ◽  
Author(s):  
Chin Moo Cho ◽  
Hee Bum Hong ◽  
Kug Sun Hong
Keyword(s):  
Thin Films ◽  
Solid Solution ◽  
Dielectric Properties ◽  
Loss Tangent ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Parameter Mismatch ◽  
Si Substrates ◽  
Bst Films

AbstractDielectric properties and structure of (1-x) BiFeO3 (BFO) - x Ba0.5Sr0.5TiO3 (BST) (x = 0 ∼1) solid solution thin films were investigated. All films were prepared at 600 oC on (111) oriented Pt / TiO2 / SiO2 / Si substrates by pulsed laser deposition (PLD) technique. Solid solution could be achieved in all composition ranges, evidenced by X-ray diffraction (XRD) and field emission scanning electric microscope (FE-SEM). The intermediate compositions (0.4 = x = 0.8) exhibited a distinct (111) oriented cubic perovskite structure, while rhombohedra symmetry was found in the x < 0.4 range. Dielectric constant and tunability of the (1-x) BFO – x BST films within this composition region (0.4 = x = 0.8) decreased from 1110 to 920 at 1 MHz, and increased from 28.34 % to 32.42 % at 200 kV/cm, respectively, while loss tangent remains constant. A systematic decrease in lattice parameter with BST addition reduced stress due to reduction of lattice parameter mismatch between film and the substrate. In that range, the improvement of the dielectric properties without a degradation of loss tangent is attributed to the presence of the stress relaxation, which was quantitatively confirmed by a surface profiler based on Stoney's equation.

Effects of LSCO Buffer Layer on the Microstructure and Dielectric Properties of Ba0.6Sr0.4TiO3 Films Prepared by Sol-gel Methods

2009 ◽  
Vol 1199 ◽  
Author(s):  
Songwei Han ◽  
Shengwen Yu ◽  
Jinrong Cheng
Keyword(s):  
Thin Films ◽  
Dielectric Properties ◽  
Sol Gel ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
Random Orientation ◽  
X Ray ◽  
Bst Thin Films ◽  
Structure And Morphology ◽  
Bst Films

AbstractIn this work, Ba0.6Sr0.4TiO3(BST) thin films were deposited on Ti substrates using conductive La0.5Sr0.5CoO3 (LCSO) as buffer layers. Both BST and LSCO films were prepared by sol-gel methods. The structure and morphology of BST and LSCO films were analyzed by X-ray diffraction (XRD). XRD results show that both BST and LSCO films have perovskite structure with random orientation. The dielectric properties of BST films were dependent on the thickness of LSCO buffer layers. Upon using LSCO buffer layers, the dielectric properties of BST films were significantly improved. The dielectric constant, tunability, and dielectric loss of BST thin films for LSCO of 150 nm achieved about 453, 0.032 and 31.26% respectively.

The Structure and Electric Field Dependent Dielectric Properties of Annealed Sr1−xBaxTio3 Ferroelectric Thin Films

1995 ◽  
Vol 401 ◽  
Author(s):  
L.A. Knauss ◽  
J.M. Pond ◽  
J.S. Horwitz ◽  
C.H. Mueller ◽  
R.E. Treece ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Properties ◽  
Single Phase ◽  
Pulsed Laser ◽  
Lattice Parameter ◽  
Laser Deposition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Deposited Films ◽  
Post Deposition

AbstractThe effect of a post deposition anneal on the structure and dielectric properties of epitaxial Sr1−x, BaxTiO3 (SBT) thin films with x = 0.35, 0.50 and 0.60 has been measured. The films were grown by pulsed laser deposition on LaAlO3(001) substrates at 750°C in 350 mTorr of oxygen. The asdeposited films were single phase, (001) oriented with 0)-scan widths for the (002) reflection between 0.160 and 0.50'. The dielectric properties of the as-deposited films exhibit a broad temperature dependence and a peak which is as much as 50 K below the peak in bulk SBT. Also, the lattice parameter, as measured by x-ray diffraction, of the as-deposited films was larger than the bulk indicating strain in the films. The as-deposited films were annealed for 8 hours at 900°C in oxygen. The dielectric properties of the annealed films were closer to that of bulk SBT and the lattice parameter was closer to the bulk lattice parameter indicating a reduction of strain. Annealing of as-deposited films also resulted in an increased dielectric tuning without increased dielectric loss.

Growth and Characterization of Ba0.5Sr0.5TiO3 Thin Films on Si (100) By 90° Off-Axis Sputtering

1994 ◽  
Vol 343 ◽  
Author(s):  
S. Y. Hou ◽  
J. Kwo ◽  
R. K. Watts ◽  
D. J. Werder ◽  
J. Shmulovich ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Rf Sputtering ◽  
Growth Conditions ◽  
Native Oxide ◽  
X Ray Diffraction ◽  
Parasitic Effect ◽  
Bst Films

ABSTRACTWe have studied BaxSr1-xTiO3 (BST) thin films (x=0.5) grown on Si (100) with and without a Pt/Ta barrier layer using 90° off-axis RF sputtering. The growth conditions were optimized according to film crystallinity, stoichiometry, and dielectric properties. Polycrystalline BST films with strong (100) texture were obtained via growth on Si (100). The measured dielectric constant from these films was low, presumably because of the parasitic effect of native oxide at BST/Si interface as revealed by TEM. On the other hand, BST films grown on Si with Pt/Ta barrier layers have crystallinity inferior to that on bare Si as determined by X-ray diffraction. Nevertheless, the best BST films on Pt/Ta layers still have good dielectric properties with dielectric constant exceeding 330, leakage current density < 1×10−6 A/cm2 (±1 V), and loss tangent 0.05 at 1 MHz.

scholarly journals Optical and dielectric properties of polycrystalline gallium ferrite thin films on Pt/Si  substrates

2020 ◽  
Author(s):  
Monali Mishra ◽  
Smrutirekha Swain ◽  
Sukalyan Dash ◽  
Somdutta Mukherjee
Keyword(s):  
Thin Films ◽  
Dielectric Properties ◽  
Sol Gel ◽  
Visible Region ◽  
Charge Carrier Concentration ◽  
Flat Band ◽  
Optical And Electrical Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates

Abstract In this work, GaFeO 3 thin films are deposited on Pt/Si substrates using sol-gel spin coating technique. The effect of these films on different properties such as: structural, optical and electrical properties are investigated. X- ray diffraction (XRD) confirms that GaFeO 3 has orthorhombic Pc2 1 n symmetry. Scanning electron microscopy reveals the uniform distribution of sol and crack free nature of the films. The optical absorption spectrum was recorded using DRS UV-Vis which showed the thin films are absorbed in the visible region. We have also performed experimentally which determines the flat band potential using Mott-Schottky equation. The width of the space charge region and charge carrier concentration of the thin films is also calculated. The dielectric properties of the thin films are also studied in this paper. This work opens up the possibility for the polycrystalline GaFeO 3 thin films to be used as phototelectrodes.

scholarly journals Thickness-dependent piezoelectric behaviour and dielectric properties of lanthanum modified BiFeo3 thin films

2011 ◽  
Vol 5 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Glenda Biasotto ◽  
Francisco Moura ◽  
Cesar Foschini ◽  
Elson Longo ◽  
Jose Varela ◽  
...  
Keyword(s):  
Thin Films ◽  
Lattice Parameter ◽  
Hexagonal Structure ◽  
Piezoelectric Response ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates ◽  
Bifeo3 Thin Films ◽  
Entire Thickness

Bi0.85La0.15FeO3 (BLFO) thin films were deposited on Pt(111)/Ti/SiO2 /Si substrates by the soft chemical method. Films with thicknesses ranging from 140 to 280 nm were grown on platinum coated silicon substrates at 500?C for 2 hours. The X-ray diffraction analysis of BLFO films evidenced a hexagonal structure over the entire thickness range investigated. The grain size of the film changes as the number of the layers increases, indicating thickness dependence. It is found that the piezoelectric response is strongly influenced by the film thickness. It is shown that the properties of BiFeO3 thin films, such as lattice parameter, dielectric permittivity, piezoeletric coefficient etc., are functions of mis?t strains.

Optical and dielectric properties of n-type polycrystalline gallium ferrite (GaFeO3) thin films on Pt/Si substrates

2021 ◽  
Author(s):  
Monali Mishra ◽  
Smrutirekha Swain ◽  
Sukalyan Dash ◽  
Somdutta Mukherjee
Keyword(s):  
Thin Films ◽  
Dielectric Properties ◽  
Si Substrates

Formation of Solid Solution and Metallic Nickel Phases During Suspension Plasma Spraying of Co Oxide and Ni Oxide

2021 ◽  
Author(s):  
Vahid Jalilvand ◽  
Ali Dolatabadi ◽  
Christian Moreau ◽  
Saeed Mohammadkhani ◽  
Lionel Roué ◽  
...  
Keyword(s):  
Solid Solution ◽  
Inert Anode ◽  
Metallic Nickel ◽  
Aluminum Production ◽  
X Ray Diffraction ◽  
Oxide Coatings ◽  
Cobalt Nickel ◽  
Sprayed Coatings ◽  
Insight Into

Abstract The focus of this study is the formation of a solid solution and metallic nickel in the cobalt-nickel mixed oxide coatings during suspension plasma spray (SPS) deposition. The (Co,Ni)O solid solution is a potential material for inert anode applications in aluminum production. SPS coatings and in-flight collected particles are studied to gain further insight into the melting and mixing phenomena of the NiO and CoO powders as well as phase formation in the deposited coatings. Moreover, the role of suspension feedstock particle sizes on the microstructure of coatings is discussed. SEM, EDS and X-ray diffraction studies helped better understanding the formation of different crystalline phases within the as-sprayed coatings. It was found that the formation of metallic nickel is possible in the coatings. The results support the importance of substrate temperature on the formation of metallic Ni, so that keeping the substrate at low temperature results in an increase of the Ni content in the coatings. In this study, possible causes for the formation of metallic Ni during spraying are discussed.

scholarly journals Elaboration of nitride thin films by reactive sputtering

2006 ◽  
Vol 59 (2) ◽  
pp. 225-232 ◽  
Author(s):  
Pierre Yves Jouan ◽  
Arnaud Tricoteaux ◽  
Nicolas Horny
Keyword(s):  
Thin Films ◽  
Compressive Stress ◽  
Bias Voltage ◽  
Substrate Surface ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
A Value ◽  
Dc Reactive Magnetron Sputtering ◽  
Nitrogen Contents

The aim of this paper is first a better understanding of DC reactive magnetron sputtering and its implications, such as the hysteresis effect and the process instability. In a second part, this article is devoted to an example of specific application: Aluminium Nitride. AlN thin films have been deposited by reactive triode sputtering. We have studied the effect of the nitrogen contents in the discharge and the RF bias voltage on the growth of AlN films on Si(100) deposited by triode sputtering. Stoichiometry and crystal orientation of AlN films have been characterized by means of Fourier-transform infrared spectroscopy, X-ray diffraction and secondary electron microscopy. Dense and transparent AlN layers were obtained at high deposition rates. These films have a (002) orientation whatever the nitrogen content in the discharge, but the best crystallised ones are obtained at low value (10%). A linear relationship was observed between the AlN lattice parameter "c" (perpendicular to the substrate surface) and the in-plane compressive stress. Applying an RF bias to the substrate leads to a (100) texture, and films become amorphous. Moreover, the film's compressive stress increases up to a value of 8GPa before decreasing slowly as the bias voltage increases.

Elaboration, Structure and Mössbauer Spectroscopy of Nanostructured Fe100−xSix Powders Elaborated by Mechanical Alloying

SPIN ◽  
2017 ◽  
Vol 07 (02) ◽  
pp. 1750002 ◽  
Author(s):  
M. Hemmous ◽  
A. Guittoum
Keyword(s):  
Magnetic Field ◽  
Solid Solution ◽  
Mechanical Alloying ◽  
Hyperfine Magnetic Field ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Sizes ◽  
The Mean ◽  
Xrd Studies

We have studied the effect of the silicon concentration on the structural and hyperfine properties of nanostructured Fe[Formula: see text]Six powders ([Formula: see text], 20, 25 and 30[Formula: see text]at.%) prepared by mechanical alloying. The X-ray diffraction (XRD) studies indicated that after 72[Formula: see text]h of milling, the solid solution bcc-[Formula: see text]-Fe(Si) is formed. The grain sizes, [Formula: see text]D[Formula: see text] (nm), decreases with increasing Si concentration and reaches a minimum value of 11[Formula: see text]nm. We have found that the lattice parameter decreases with increasing Si concentration. The changes in values are attributed to the substitutional dissolution of Si in Fe matrix. From the adjustment of Mössbauer spectra, we have shown that the mean hyperfine magnetic field, [Formula: see text]H[Formula: see text] (T), decreases with increasing Si concentration. The substitutional dependence of [Formula: see text]H[Formula: see text] (T) can be attributed to the effect of p electrons Si influencing electrons d of Fe.

scholarly journals Dielectric and electrical properties of Cr substituted Mg ferrites

2015 ◽  
Vol 39 (1) ◽  
pp. 1-12 ◽  
Author(s):  
AKM Zakaria ◽  
Faizun Nesa ◽  
MA Saeed Khan ◽  
SM Yunus ◽  
NI Khan ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Lattice Parameter ◽  
Activation Energies ◽  
X Ray Diffraction ◽  
Constant E ◽  
Cr Concentration ◽  
Academy Of Sciences

The spinel ferrites MgCrxFe2-xO4 (0.0 ? × ?1.0) were prepared through the solid state reaction using conventional ceramic method at 1300°C in air. The homogeneous phase of the ferrite samples was observed from the X-ray diffraction study. Lattice parameter of the samples was found to decrease with increasing Cr concentration in the system obeying Vegard’s law. The ac electrical resistivity, measured as a function of temperature, decreases with the increase of temperature indicating the semiconducting nature of all the samples. The activation energies were calculated and found to decrease with increasing Cr content. The lower activation energies are associated with higher electrical conductivity. With the increase of temperature, dielectric constant (e`) and dielectric loss tangent are observed to be increased; while with the increase of frequency, dielectric constant (e`) and dielectric loss tangent decrease for all the samples.Journal of Bangladesh Academy of Sciences, Vol. 39, No. 1, 1-12, 2015

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