Preparation of Na0.5K0.5NbO3/La0.6Sr0.2Mn1.2O3/LaAlO3 Thin Film Structures by Pulsed Laser Deposition

1999 ◽  
Vol 574 ◽  
Author(s):  
Choong-Rae Cho ◽  
S. I. Khartsev ◽  
A. M. Grishin ◽  
Ture Lindbäick
Keyword(s):  
Dielectric Permittivity ◽  
Room Temperature ◽  
Single Phase ◽  
Pulsed Laser ◽  
Dissipation Factor ◽  
Processing Parameters ◽  
X Ray Diffraction ◽  
Axis Orientation ◽  
X Ray ◽  
Tan Δ

AbstractWe report on ferroelectric/giant magnetoresistive Na0.5K0.5NbO3/La0.6Sr0.2Mn1.2O3 (NKN/LSMO) heterostructures grown onto LaAlO3 (001) single crystal using KrF pulsed laser ablation of stoichiometric ceramic target. Main processing parameters have been optimized to obtain smooth LSMO template layer, avoid NKN-LSMO interdiffusion, preserve NKN stoichiometry against the lost of volatile potassium and sodium and achieve reasonable reliability of NKN film performance. X-ray diffraction θ- 2θ scans and rocking curves evidence for single-phase content and high c-axis orientation both in template LSMO and top NKN layers. Ferroelectric measurements yield remnant polarization Pr of 1.5 [C/cm2 and spontaneous polarization Ps of 7 μC/cm2 at electric field strength of 130 kV/cm. At room temperature, dielectric permittivity ε′ and dissipation factor tan δ have been found to vary from 595 to 555 and 0.046 to 0.029 respectively in the frequency range of 0.4 to 20 kHz. At 10 kHz dielectric permittivity linearly increases from 410 to 650 in the temperature range 77 K to 415 K while the dissipation factor below 320 K does not exceed 3%.

scholarly journals Preparation of ZnO film on p-Si Substrate by Silar and Heterojunction Characteristics of p-Si/n-Zno

2011 ◽  
Vol 8 (1) ◽  
pp. 197-200 ◽  
Author(s):  
P. Mitra
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Reverse Current ◽  
X Ray Diffraction ◽  
Zno Film ◽  
Si Substrate ◽  
Current Ratio ◽  
Axis Orientation ◽  
X Ray ◽  
Maximum Value

Zinc oxide (ZnO) thin films was deposited on p-silicon (Si) substrate from ammonium zincate bath following a chemical dipping technique called SILAR. Structural characterization by X-ray diffraction (XRD) indicates the formation of polycrystalline single phase ZnO with strong c-axis orientation. I-V characteristic of the p-Si/n-ZnO heterojunction was studied and rectification was observed. The maximum value of forward to reverse current ratio at room temperature was ~15 at 3.0 V. It increases to ~30 at 100oC.

Impedance Spectroscopy Study of LiTaO3 Powder Synthesized via Sol-Gel Method

2012 ◽  
Vol 545 ◽  
pp. 275-278 ◽  
Author(s):  
Lili Widarti Zainuddin ◽  
Norlida Kamarulzaman
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Sol Gel ◽  
Rhombohedral Structure ◽  
Spectroscopy Study ◽  
X Ray Diffraction ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Impedance Spectroscopy Study

A ceramics sample of LiTaO3 was prepared using a sol-gel method. The sample is annealed at 750 °C for 48 hours. X-ray diffraction analysis indicate the formation of single phase, rhombohedral structure. An ac impedance study was used to analyse the conductivity of LiTaO3 at room temperature and at various temperatures.

scholarly journals Equimolar Yttria-Stabilized Zirconia and Samaria-Doped Ceria Solid Solutions

Ceramics ◽  
2018 ◽  
Vol 1 (2) ◽  
pp. 343-352 ◽  
Author(s):  
Reginaldo Muccillo ◽  
Daniel de Florio ◽  
Eliana Muccillo
Keyword(s):  
Tetragonal Phase ◽  
Room Temperature ◽  
Single Phase ◽  
Rietveld Analysis ◽  
X Ray Diffraction ◽  
Ceramic Powders ◽  
Stabilized Zirconia ◽  
X Ray ◽  
Ceria Solid Solutions ◽  
Attrition Milling

Compositions of (ZrO2)0.92(Y2O3)0.08 (zirconia: 8 mol % yttria—8YSZ) and (CeO2)0.8(Sm2O3)0.2 (ceria: 20 mol % samaria—SDC20) ceramic powders were prepared by attrition milling to form an equimolar powder mixture, followed by uniaxial and isostatic pressing. The pellets were quenched to room temperature from 1200 °C, 1300 °C, 1400 °C and 1500 °C to freeze the defects configuration attained at those temperatures. X-ray diffraction analyses, performed in all quenched pellets, show the evolution of the two (8YSZ and SDC20) cubic fluorite structural phases to a single phase at 1500 °C, identified by Rietveld analysis as a tetragonal phase. Impedance spectroscopy analyses were carried out in pellets either quenched or slowly cooled from 1500 °C. Heating the quenched pellets to 1000 °C decreases the electrical resistivity while it increases in the slowly cooled pellets; the decrease is ascribed to annealing of defects created by lattice micro-tensions during quenching while the increase to partial destabilization of the tetragonal phase.

Study of Raman Spectrum of Fe Doped CeO2 Thin Films Grown by Pulsed Laser Deposition

2010 ◽  
Vol 123-125 ◽  
pp. 375-378 ◽  
Author(s):  
Ram Prakash ◽  
Shalendra Kumar ◽  
Chan Gyu Lee ◽  
S.K. Sharma ◽  
Marcelo Knobel ◽  
...  
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Single Phase ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Fe Doping ◽  
Full Width ◽  
Deposition Technique ◽  
X Ray Diffraction ◽  
X Ray

Ce1-xFexO2 (x=0, 0.01, 0.03 and 0.0 5) thin films were grown by pulsed laser deposition technique on Si and LaAlO3 (LAO) substrates. These films were deposited in vacuum and 200 mTorr oxygen partial pressure for both the substrates. These films were characterized by x-ray diffraction XRD and Raman spectroscopy measurements. XRD results reveal that these films are single phase. Raman results show F2g mode at ~466 cm-1 and defect peak at 489 cm-1 for film that deposited on LAO substrates, full width at half maximum (FWHM) is increasing with Fe doping for films deposited on both the substrates.

scholarly journals Structure and electric properties of cerium substituted SrBi1.8Ce0.2Nb2O9 and SrBi1.8Ce0.2Ta2O9 ceramics

2016 ◽  
Vol 10 (3) ◽  
pp. 183-188 ◽  
Author(s):  
Mohamed Afqir ◽  
Amina Tachafine ◽  
Didier Fasquelle ◽  
Mohamed Elaatmani ◽  
Jean-Claude Carru ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Solid State ◽  
Room Temperature ◽  
Single Phase ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
Lcr Meter ◽  
Curie Temperature Tc

SrBi1.8Ce0.2Nb2O9 (SBCN) and SrBi1.8Ce0.2Ta2O9 (SBCT) powders were prepared via solid-state reaction method. X-ray diffraction analysis reveals that the SBCN and SBCT powders have the single phase orthorhom-bic Aurivillius structure at room temperature. The contribution of Raman scattering and FTIR spectroscopy of these samples were relatively smooth and resemble each other. The calcined powders were uniaxially pressed and sintered at 1250?C for 8 h to obtaine dense ceramics. Dielectric constant, loss tangent and AC conductivity of the sintered Ce-doped SrBi2Nb2O9 and SrBi2Ta2O9 ceramics were measured by LCR meter. The Ce-doped SBN (SBCN) ceramics have a higher Curie temperature (TC) and dielectric constant at TC (380?C and ?? ~3510) compared to the Ce-doped SBT (SBCT) ceramics (330?C and ?? ~115) when measured at 100Hz. However, the Ce-doped SBT (SBCT) ceramics have lower conductivity and dielectric loss.

scholarly journals Ferromagnetic Order in the Intermetallic Alloys laNi5-xMgx

2012 ◽  
Vol 29 (1) ◽  
pp. 50
Author(s):  
D.N Ba ◽  
L.T Tai ◽  
N.T Trung ◽  
N.T Huy
Keyword(s):  
Magnetic Properties ◽  
Curie Temperature ◽  
Room Temperature ◽  
Single Phase ◽  
Chemical Doping ◽  
Intermetallic Alloys ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ferromagnetic Order ◽  
Diffraction Patterns

The influences of the substitution of Ni with Mg on crystallographic and magnetic properties of the intermetallic alloys LaNi5-xMgx (x ≤ 0.4) were investigated. The X-ray diffraction patterns showed that all samples were of single phase, and the lattice parameters, a and c, decreased slightly upon chemical doping. LaNi5 is well known as an exchange-enhanced Pauli paramagnet. Interestingly, in LaNi5-xMgx, the ferromagnetic order existed even with a small amount of dopants; the Curie temperature reached the value of room temperature for x = 0.2, and enhanced with increasing x.

Synthesis and Luminescence Properties of Chalcopyrite-Type CuAlS2

2006 ◽  
Vol 301 ◽  
pp. 177-180 ◽  
Author(s):  
Yuichiro Kuroki ◽  
Tomoichiro Okamoto ◽  
Masasuke Takata
Keyword(s):  
Diffraction Analysis ◽  
Room Temperature ◽  
Single Phase ◽  
Elevated Temperatures ◽  
Emission Peak ◽  
Maximum Intensity ◽  
X Ray Diffraction ◽  
Ultraviolet Emission ◽  
X Ray ◽  
Copper Aluminum

Copper aluminum disulfide (CuAlS2) powders were synthesized in an evacuated ampoule at elevated temperatures. X-ray diffraction analysis revealed that the powders heated at temperatures higher than 800oC were single-phase CuAlS2. In the cathodoluminescence (CL) spectra measured at room temperature, the powders heated at temperatures higher than 600oC exhibited a visible emission peak at approximately 1.8 eV and a distinct ultraviolet emission peak at 3.45 eV. The powder heated at 700oC showed the maximum intensity of ultraviolet emission which is considered to be associated with excitons.

scholarly journals Effect of TeO2 addition on the dielectric properties of CaCu3Ti4O12 ceramics derived from the oxalate precursor route

2013 ◽  
Vol 03 (04) ◽  
pp. 1350028 ◽  
Author(s):  
P. Thomas ◽  
K. B. R. Varma
Keyword(s):  
Dielectric Properties ◽  
Dielectric Loss ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Oxalate Precursor ◽  
X Ray ◽  
Practical Applications ◽  
Low Dielectric ◽  
Precursor Route ◽  
Tan Δ

CaCu 3 Ti 4 O 12 (CCTO) ceramics which has perovskite structure gained considerable attention due to its giant permittivity. But it has high tan δ (0.1 at 1 kHz) at room temperature, which needs to be minimized to the level of practical applications. Hence, TeO 2 which is a good glass former has been deliberately added to CCTO nanoceramic (derived from the oxalate precursor route) to explore the possibility of reducing the dielectric loss while maintaining the high permittivity. The structural, morphological and dielectric properties of the pure CCTO and TeO 2 added ceramics were studied using X-ray diffraction, Scanning Electron Microscope along with Energy Dispersive X-ray Analysis (EDX), spectroscopy and Impedance analyzer. For the 2.0 wt.% TeO 2 added ceramics, there is a remarkable difference in the microstructural features as compared to that of pure CCTO ceramics. This sample exhibited permittivity values as high as 7387 at 10 KHz and low dielectric loss value of 0.037 at 10 kHz, which can be exploited for the high frequency capacitors application.

Zinc Oxide Nano Walls Synthesized by Chemical Vapor Deposition

2014 ◽  
Vol 608 ◽  
pp. 127-131 ◽  
Author(s):  
Suttinart Noothongkaew ◽  
Supakorn Pukird ◽  
Worasak Sukkabot ◽  
Ki Seok An
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Green Emission ◽  
X Ray Diffraction ◽  
Ultraviolet Emission ◽  
Axis Orientation ◽  
X Ray ◽  
Zno Nanostructure

ZnO nanowalls were synthesized by chemical vapor deposition at temperature of 650 °C for 1 hour on the silicon substrate. The morphologies of samples were characterized by scanning electron microscopy (SEM). The result from X-ray diffraction (XRD) confirmed that the ZnO nanowalls were vertical c-axis orientation. A room temperature Photoluminescence peak at 378 nm is ultraviolet emission (UV) and the broad peak at wavelengths around 450-650 nm is corresponding to the green emission of ZnO nanostructure. This synthesis may be applicable for gas sensor or solar cells.

scholarly journals Study of multiferroic properties of Bi2Fe2WO9 ceramic for device application

2016 ◽  
Vol 06 (03) ◽  
pp. 1650023 ◽  
Author(s):  
Jyoshna Rout ◽  
R. N. P. Choudhary
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Electrical Parameters ◽  
Orthorhombic Crystal ◽  
Solid State Reaction Technique ◽  
X Ray ◽  
Universal Power Law ◽  
Phase Compound ◽  
Comprehensive Study

The Bi2Fe2WO9 ceramic was prepared using a standard solid-state reaction technique. Preliminary analysis of X-ray diffraction pattern revealed the formation of single-phase compound with orthorhombic crystal symmetry. The surface morphology of the material captured using scanning electron microscope (SEM) exhibits formation of a densely packed microstructure. Comprehensive study of dielectric properties showed two anomalies at 200[Formula: see text]C and 450[Formula: see text]C: first one may be related to magnetic whereas second one may be related to ferroelectric phase transition. The field dependent magnetic study of the material shows the existence of small remnant magnetization ([Formula: see text]) of 0.052[Formula: see text]em[Formula: see text]/g at room temperature. The existence of magneto-electric (ME) coupling coefficient along with above properties confirms multi-ferroic characteristics of the compound. Selected range temperature and frequency dependent electrical parameters (impedance, modulus, conductivity) of the compound shows that electric properties are correlated to its microstructure. Detailed studies of frequency dependence of ac conductivity suggest that the material obeys Jonscher’s universal power law.

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