Characterization of Laser-Assisted Pulseid Laser Deiposited BaFe12O19

1992 ◽  
Vol 285 ◽  
Author(s):  
J.S. Horwitz ◽  
D.B. Chrisey ◽  
K.S. Grabowski ◽  
C.A. Carosella ◽  
P. Lubitz ◽  
...  

ABSTRACTHigh quality, epitaxial barium hexaferrite (BaFe12O19) thin films have been deposited by pulsed laser deposition (PLD) onto basal plane sapphire at substrate temperatures of 900°C in 400 mTorr of oxygen. Thin films (< 500 nm) were smooth while thick films (> 1000 nm) had rough, polycrystalline surfaces and “soot-like” appearances. The integration of ferrite films with semiconductors will require thick films (< 70 μm) and low substrate processing temperatures (≤ 600°C). Films deposited at 600°C were mostly amorphous with the presence of some crystalline, non-hexaferrite material. In an effort to improve the quality of barium hexaferrite fihns, we have investigated the effects of excimer-laser-assisted PLD (LAPLD) on the growth of BaFe12O19. During the deposition, the substrate was illuminated with the output of a second pulsed excimer laser (KrF) weakly focused to an energy of 10 to 130 mJ/cm2. The output of the second laser was synchronized such that the delay between the vaporization laser and the annealing laser was 0 to 1 ms. The X-ray diffraction analysis of LAPLD films deposited at 600°C with an annealing fluence of 50 mJ/cm2 indicated that the films were a crystalline mixture of hexaferrite and non-hexaferrite phases. Both phases exhibited a preferred orientation characterized by narrow x-ray rocking curve widths (FWHM ∼ 1°). Magnetic properties (magnetic moment, saturation magnetization and coercive field) detennined from a vibrating sample magnetometer (VSM) also confirmed the presence of oriented hexaferrite material in the laser annealed samples. These results show clear advantages of LAPLD for improved structural and magnetic properties of BaFe12O19 deposited at substrate temperatures compatible with semiconducting materials.

1998 ◽  
Vol 83 (1) ◽  
pp. 174-180 ◽  
Author(s):  
Guolin Yu ◽  
Kalaga Murali Krishna ◽  
Chunlin Shao ◽  
Masayoshi Umeno ◽  
Tetsuo Soga ◽  
...  

1988 ◽  
Vol 140 ◽  
Author(s):  
M. S. Donley ◽  
P. T. Murray ◽  
N. T. McDevitt

AbstractThe growth and characterization of MoS thin films grown by pulsed laser evaporation is investigated. TOF anafysis of the ions evaporated from an MoS2 target indicates that PLE results primarily in the evaporation of atomic Mo and S species; MoxSy clusters were also detected, but were present at a significantly Iower intensity. TOF velocity analysis indicates an effective plasma temperature of 1500K. Stoichiometric MoS2 films were grown at substrate temperatures between room temperature and 500ºC under the above laser conditions. XPS data is used to develop a Wagner chemical state plot. Analysis of the films by Raman spectroscopy and glancing angle x-ray diffraction indicates the films to be crystalline, hexagonal MoS2, with a tendency for basal plane orientation parallel to the substrate.


MRS Advances ◽  
2015 ◽  
Vol 1 (3) ◽  
pp. 203-208 ◽  
Author(s):  
Hrishikesh Kamat ◽  
Xingwu Wang ◽  
James Parry ◽  
Yueling Qin ◽  
Hao Zeng

ABSTRACTIron nitride thin films have potential applications in the biomedicine and energy. The magnetic properties of these films can be tuned by incorporating copper nitride. In this study, iron copper nitride thin films have been fabricated by magnetron sputtering technique either by co-sputtering iron nitride and copper nitride or by layer stacking of the materials. The structure, morphology and magnetic properties of the films have been studied by scanning electron microscopy, x-ray diffraction, x-ray reflectivity and vibrating sample magnetometry.


1986 ◽  
Vol 77 ◽  
Author(s):  
O. F. De Lima ◽  
Y. Lepetre ◽  
M. B. Brodsky

ABSTRACTTEM, X-ray diffraction, and electrical resistivity measurements were used to study the microstructure and the growth of AI-Cr-AI film sandwiches, where the individual Al layers were 300 Å thick and the Cr thickness was varied between 0–10 atomic layers. The base vacuum was around 1.0 × 10−10 torr, substrate temperatures varied between 100–350 °C, and evaporation rates were 3Å/s for Al and ∼0.1 – 0.2 Å/s for Cr. All Al films had a strong (111) texture and showed a non-percolative island structure at 350 °C. The films became connected at lower substrate temperatures, reaching perfect continuity at 100°C. However, electrical conductivity is achieved also for the films deposited at 350 °C when one or more atomic layers of Cr are sandwiched between the Al layers. Results for the superconducting critical temperature and resistivity are discussed in terms of Cr diffusion into Al and the film size effect.


2006 ◽  
Vol 514-516 ◽  
pp. 207-211 ◽  
Author(s):  
Fátima Cardoso ◽  
Bernardo G. Almeida ◽  
Pedro Caldelas ◽  
Jorge A. Mendes

The ferroelectric polymorph of lead metaniobate (PbNb2O6) presents an orthorhombic structure that is metastable at room temperature. This phase is obtained by quenching from high temperature. The fabrication of lead niobate thin films with this orthorhombic form has been reported to be difficult due to the presence of phases with the rhombohedric form or other nonstoichiometric phases. In this work, lead niobate thin films have been prepared by laser ablation, at different oxygen pressures and with different substrate temperatures. Their structure was studied by X-ray diffraction and their surface was examined by scanning electron microscopy (SEM). The results show that for low deposition temperatures the films presented a rhombohedric-PbNb2O6 structural phase. As Tdep increases the films started to develop an orthorhombic- PbNb2O6 structure that appeared at 400°C and remains up to 600°C. For lower oxygen pressure during deposition, a mixture of this phase and other orthorhombic lead deficient phases are present in the films. On the other hand, by increasing the oxygen pressure the lead deficient phases are strongly reduced and the films present only the orthorhombic- PbNb2O6 structure.


2020 ◽  
Vol 43 (1) ◽  
pp. 26-42 ◽  
Author(s):  
Zahra Hajian Karahroudi ◽  
Kambiz Hedayati ◽  
Mojtaba Goodarzi

AbstractThis study presents a preparation of SrFe12O19– SrTiO3 nanocomposite synthesis via the green auto-combustion method. At first, SrFe12O19 nanoparticles were synthesized as a core and then, SrTiO3 nanoparticles were prepared as a shell for it to manufacture SrFe12O19–SrTiO3 nanocomposite. A novel sol-gel auto-combustion green synthesis method has been used with lemon juice as a capping agent. The prepared SrFe12O19–SrTiO3 nanocomposites were characterized by using several techniques to characterize their structural, morphological and magnetic properties. The crystal structures of the nanocomposite were investigated via X-ray diffraction (XRD). The morphology of SrFe12O19– SrTiO3 nanocomposite was studied by using a scanning electron microscope (SEM). The elemental composition of the materials was analyzed by an energy-dispersive X-ray (EDX). Magnetic properties and hysteresis loop of nanopowder were characterized via vibrating sample magnetometer (VSM) in the room temperature. Fourier transform infrared spectroscopy (FTIR) spectra of the samples showed the molecular bands of nanoparticles. Also, the photocatalytic behavior of nanocomposites has been checked by the degradation of azo dyes under irradiation of ultraviolet light.


2012 ◽  
Vol 90 (1) ◽  
pp. 39-43 ◽  
Author(s):  
X. Xiang ◽  
D. Chang ◽  
Y. Jiang ◽  
C.M. Liu ◽  
X.T. Zu

Anatase TiO2 thin films are deposited on K9 glass samples at different substrate temperatures by radio frequency magnetron sputtering. N ion implantation is performed in the as-deposited TiO2 thin films at ion fluences of 5 × 1016, 1 × 1017, and 5 × 1017 ions/cm2. X-ray diffraction, atomic force microscope, X-ray photoelectron spectroscopy (XPS), and UV–visible spectrophotometer are used to characterize the films. With increasing N ion fluences, the absorption edges of anatase TiO2 films shift to longer wavelengths and the absorbance increases in the visible light region. XPS results show that the red shift of TiO2 films is due to the formation of N–Ti–O compounds. As a result, photoactivity is enhanced with increasing N ion fluence.


2013 ◽  
Vol 665 ◽  
pp. 254-262 ◽  
Author(s):  
J.R. Rathod ◽  
Haresh S. Patel ◽  
K.D. Patel ◽  
V.M. Pathak

Group II-VI compounds have been investigated largely in last two decades due to their interesting optoelectronic properties. ZnTe, a member of this family, possesses a bandgap around 2.26eV. This material is now a day investigated in thin film form due to its potential towards various viable applications. In this paper, the authors report their investigations on the preparation of ZnTe thin films using vacuum evaporation technique and their structural and optical characterizations. The structural characterization, carried out using an X-ray diffraction (XRD) technique shows that ZnTe used in present case possesses a cubic structure. Using the same data, the micro strain and dislocation density were evaluated and found to be around 1.465×10-3lines-m2and 1.639×1015lines/m2respecctively. The optical characterization carried out in UV-VIS-NIR region reveals the fact that band gap of ZnTe is around 2.2eV in present case. In addition to this, it was observed that the value of bandgap decreases as the thickness of films increases. The direct transitions of the carries are involved in ZnTe. Using the data of UV-VIS-NIR spectroscopy, the transmission coefficient and extinction coefficient were also calculated for ZnTe thin films. Besides, the variation of extinction coefficient with wavelength has also been discussed here.


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