Nonstoichiometry of Epitaxial FeTiO3+δ Films

2002 ◽  
Vol 746 ◽  
Author(s):  
Tatsuo Fujii ◽  
Makoto Sadai ◽  
Masakazu Kayano ◽  
Makoto Nakanishi ◽  
Jun Takada
Keyword(s):  
Substrate Temperature ◽  
Oxygen Pressure ◽  
Room Temperature ◽  
Oxygen Nonstoichiometry ◽  
Epitaxial Thin Films ◽  
Helicon Plasma ◽  
Sputtering Deposition ◽  
Plasma Sputtering ◽  
Valence States ◽  
Fe Ions

ABSTRACTEpitaxial thin films of (001)-oriented FeTiO3+δ were prepared on α-Al2O3(001) single crystalline substrates by helicon plasma sputtering technique. The FeTiO3+δ films had large oxygen nonstoichiometry, which seriously depended on both substrate temperature and oxygen pressure during the sputtering deposition. The valence states of Fe ions in FeTiO3+δ changed monotonically from Fe2+ to Fe3+ with decreasing the substrate temperature from 900 to 400°C or with increasing the oxygen pressure from 0.9 to 1.8×10-6 Pa. The change of Fe valence states from Fe2+ to Fe3+ induced the magnetic phase transition only for the films prepared at 900°C. The films containing Fe2+ were paramagnetic while those with Fe3+ were antiferromagnetic at room temperature. The oxygen nonstoichiometry of the FeTiO3+δ films was probably produced by cation vacancies and disarrangement of Fe3+ and Ti4+ ions, which randomly occupied both interstitial and substitutional sites of the FeTiO3 related structure.

QUICK SYNTHESIS OF CARBON NITRIDE FILMS BY NEW DC HOLLOW CATHODE PLASMA SPUTTERING DEPOSITION TECHNIQUE

2005 ◽  
Vol 19 (30) ◽  
pp. 4437-4447 ◽  
Author(s):  
P. YANG ◽  
X. P. FENG ◽  
Y. C. SHI ◽  
Y. H. YAN ◽  
J. ZHANG
Keyword(s):  
Substrate Temperature ◽  
Hollow Cathode ◽  
Fourier Transformation ◽  
Carbon Nitride ◽  
Room Temperature ◽  
Particle Energy ◽  
Deposition Technique ◽  
Cathode Plasma ◽  
Sputtering Deposition ◽  
Plasma Sputtering

High N content of carbon nitride films are quickly deposited onto Si (100) substrates at room temperature by using DC hollow cathode plasma sputtering deposition technique. The deposition rate is up to 283 nm/min at the bias voltage of 400 V. The properties of the films are characterized by using XPS, Raman (scattering) and Fourier transformation infrared (FTIR) spectroscopy. Experiments results provide direct evidences that the structures of CN films can be controlled by regulating bias voltages. The maximum sp3 C – N concentration up to 0.73 is obtained. Raman data is used to confirm XPS results. FTIR of the films clearly show C – N and C = N components (1000–1800 cm-1) together with a tiny peak C ≡ N (2181 cm-1). By reducing particle energy and substrate temperature, we have succeeded in suppressing the mechanisms of losing N -contain species during deposition, and achieved a large amount of sp3 bonds of CN films.

Properties of Binary Si:H Materials Prepared by Hydrogen Plasma Sputtering

1989 ◽  
Vol 164 ◽  
Author(s):  
Shoji Furukawa ◽  
Tatsuro Miyasato
Keyword(s):  
Substrate Temperature ◽  
Room Temperature ◽  
Hydrogen Plasma ◽  
Rf Sputtering ◽  
Hydrogen Atmosphere ◽  
Pure Hydrogen ◽  
Rf Power ◽  
Optical Gap ◽  
Plasma Sputtering ◽  
X Ray Scattering

AbstractBinary Si:H materials are prepared by means of the rf sputtering technique in pure hydrogen atmosphere on low temperature (about 100 K) and room temperature substrates. The physical properties of the obtained materials are very much affected by the rf power and substrate temperature during the deposition. The material prepared at a low substrate temperature with a low rf power has a wide optical gap, and shows a visible photoluminescence at room temperature. On the other hand, the material prepared at room temperature with a high rf power contains many Si microcrystals, whose diameters are relatively large, and its optical gap becomes very small. The latter condition causes the dependence of the crystalline direction of the material film on the substrate crystal even at the room temperature. An rf power-modulated multi-layered structure (superlattice) is also proposed, and an apparent diffraction peak can be observed in the low-angle X-ray scattering measurement.

FeTiO3/Fe2O3 Multilayered Films for New Magnetic Semiconductors above Room Temperature

2006 ◽  
Vol 45 ◽  
pp. 1309-1315 ◽  
Author(s):  
Tatsuo Fujii ◽  
Yusuke Takada ◽  
Jun Takada
Keyword(s):  
Solid Solution ◽  
Room Temperature ◽  
Magnetic Semiconductors ◽  
Depth Profiling ◽  
Magnetic Coupling ◽  
Multilayered Films ◽  
Helicon Plasma ◽  
Plasma Sputtering ◽  
Magnetic And Electric Properties ◽  
Α Al2o3

Well-crystallized Fe1.18Ti0.82O3 and Fe1.18Ti0.82O3/Fe2O3 bilayered films were successfully prepared by using reactive helicon plasma sputtering technique. The solid solution films, Fe2−xTixO3, between hematite (α-Fe2O3) and ilmenite (FeTiO3) with various Ti concentrations, x, were epitaxially formed on the α-Al2O3(0001) single-crystalline substrates. The magnetic and electric properties of the solid solution films were systematically changed with increasing the Ti concentration. The film with the intermediate composition of Fe1.18Ti0.82O3 had the largest saturation magnetization at low temperature. However, the TC of solid solution films was linearly decreased with increasing the Ti concentration. The Fe1.18Ti0.82O3 film without Fe2O3 layers showed lower TC of about 200 K, while the TC of the Fe1.18Ti0.82O3/Fe2O3 bilayered film increased to about 220 K. The strong magnetic coupling between layers seemed to increase the TC of the attached Fe1.18Ti0.82O3 layer. The sharp interface between Fe1.18Ti0.82O3 and α-Fe2O3 layers was confirmed by the XPS depth profiling.

Exchange Coupling and Spin-Flip Transition of CoFe2O4/α-Fe2O3 Bilayered Films

2001 ◽  
Vol 674 ◽  
Author(s):  
Tatsuo Fujii ◽  
Takuya Yano ◽  
Makoto Nakanishi ◽  
Jun Takada
Keyword(s):  
Magnetic Anisotropy ◽  
Exchange Coupling ◽  
Room Temperature ◽  
Film Plane ◽  
Spin Axis ◽  
Base Layer ◽  
Helicon Plasma ◽  
Polycrystalline Layer ◽  
Plasma Sputtering ◽  
Spin Flip

ABSTRACTCoFe2O4/α-Fe2O3 (ferrimagnetic / antiferromagnetic) bilayered films were prepared on α-Al2O3(102) single-crystalline substrates by helicon plasma sputtering. A well-crystallized epitaxial α-Fe2O3(102) layer was formed on the substrate, while CoFe2O4 grown on α-Fe2O3(102) was a polycrystalline layer with a (100)-preferred orientation. The α-Fe2O3(102) films without CoFe2O4 layers clearly showed a spin-flip transition at about 400 K. The spins aligned perpendicular to the film plane at room temperature changed their direction within the film plane above 400 K. However the α-Fe2O3 base layers of CoFe2O4/α-Fe2O3 bilayered films did not show any spin-flip transition. The CoFe2O4 layer on α-Fe2O3 had a large in-plane magnetic anisotropy, while the spin axis of the α-Fe2O3(102) base layer was directed perpendicular to the film plane. The magnetization of ferrimagnetic CoFe2O4 layers was coupled perpendicularly to the spin axis of anitiferromagnetic α-Fe2O3 layers due to the exchange coupling at the interface between CoFe2O4 and α-Fe2O3.

Dependence of Composition and Microstructure of RuOx Films on Target Status and Substrate Temperature in Reactive Sputtering Deposition

1996 ◽  
Vol 433 ◽  
Author(s):  
Q. Wang ◽  
K.-A. Yang ◽  
A. Franciosi ◽  
D. F. Evans ◽  
W. L. Gladfelter
Keyword(s):  
Substrate Temperature ◽  
Crystalline Structure ◽  
Room Temperature ◽  
Rutherford Backscattering Spectrometry ◽  
Ruthenium Oxide ◽  
Target Surface ◽  
Reactive Sputtering ◽  
Sputtering Deposition ◽  
Surface Conditions ◽  
Metallic Target

AbstractRuthenium oxide films were deposited on Al2O3 (0001) and (1102) substrates using reactive sputtering under two different target surface conditions. Films grown when the surface of the target was metallic ruthenium (metallic-target) showed a Ru: O ratio of 1: 2.0±0.05 as determined by Rutherford backscattering spectrometry. At elevated deposition temperatures, these films aligned with the substrates as RuO2 (100) ║ A12O3 (0001) and RuO2 (101) ║ Al2O3(1102). Films deposited when the target surface was fully oxidized (oxidized-target) exhibited a Ru: O ratio of 1: 2.5±0.05 and displayed an oriented crystalline structure even at room temperature. The resistivity of the RuO2.5 films was 75 μΩ-cm and was independent of temperature between 5 and 300 K. Possible causes of this behavior are discussed.

Influence of Momentary Annealing on the Nanoscale Surface Morphology of Room Temperature Pulsed Laser Deposited NiO(111) Epitaxial Thin Films on Atomically Stepped Sapphire (0001) Substrates

2013 ◽  
Vol 1507 ◽  
Author(s):  
Ryosuke Yamauchi ◽  
Geng Tan ◽  
Daishi Shiojiri ◽  
Nobuo Tsuchimine ◽  
Koji Koyama ◽  
...  
Keyword(s):  
Thin Films ◽  
Surface Morphology ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Film Surface ◽  
Transient State ◽  
Epitaxial Thin Films ◽  
Flat Surfaces ◽  
Surface Nanostructure ◽  
Atomically Flat

ABSTRACTWe examined the influence of momentary annealing on the nanoscale surface morphology of NiO(111) epitaxial thin films deposited on atomically stepped sapphire (0001) substrates at room temperature in O2 at 1.3 × 10−3 and 1.3 × 10−6 Pa using a pulsed laser deposition (PLD) technique. The NiO films have atomically flat surfaces (RMS roughness: approximately 0.1–0.2 nm) reflecting the step-and-terrace structures of the substrates, regardless of the O2 deposition pressure. After rapid thermal annealing (RTA) of the NiO(111) epitaxial film deposited at 1.3 × 10−3 Pa O2, a periodic straight nanogroove array related to the atomic steps of the substrate was formed on the film surface for 60 s. In contrast, the fabrication of a transient state in the nanogroove array formation was achieved with RTA of less than 1 s. However, when the O2 atmosphere during PLD was 1.3 × 10−6 Pa, random crystal growth was observed and resulted in a disordered rough surface nanostructure after RTA.

Oxidation of Fe-24%Cr-11%Mo at room temperature and low oxygen pressure

1989 ◽  
Vol 214 (3) ◽  
pp. A267
Author(s):  
C. Palacio ◽  
H.J. Mathieu ◽  
D. Landolt
Keyword(s):  
Oxygen Pressure ◽  
Room Temperature ◽  
Low Oxygen ◽  
Low Oxygen Pressure

AFM Study of Surface Morphology of Aluminum Nitride Thin Films

1995 ◽  
Vol 388 ◽  
Author(s):  
Yoshihisa Watanabe ◽  
Yoshikazu Nakamura ◽  
Shigekazu Hirayama ◽  
Yuusaku Naota
Keyword(s):  
Thin Films ◽  
Surface Morphology ◽  
Substrate Temperature ◽  
Single Crystal ◽  
Room Temperature ◽  
Ion Beam ◽  
Soda Lime ◽  
Silicon Single Crystal ◽  
Soda Lime Glass ◽  
Average Roughness

AbstractAluminum nitride (AlN) thin films have been synthesized by ion-beam assisted deposition method. Film deposition has been performed on the substrates of silicon single crystal, soda-lime glass and alumin A. the influence of the substrate roughness on the film roughness is studied. the substrate temperature has been kept at room temperature and 473K and the kinetic energy of the incident nitrogen ion beam and the deposition rate have been fixed to 0.5 keV and 0.07 nm/s, respectively. the microstructure of the synthesized films has been examined by X-ray diffraction (XRD) and the surface morphology has been observed by atomic force microscopy(AFM). IN the XRD patterns of films synthesized at both room temperature and 473K, the diffraction line indicating the alN (10*0) can be discerned and the broad peak composed of two lines indicating the a1N (00*2) and a1N (10*1) planes is also observed. aFM observations for 100 nm films reveal that (1) the surface of the films synthesized on the silicon single crystal and soda-lime glass substrates is uniform and smooth on the nanometer scale, (2) the average roughness of the films synthesized on the alumina substrate is similar to that of the substrate, suggesting the evaluation of the average roughness of the film itself is difficult in the case of the rough substrate, and (3) the average roughness increases with increasing the substrate temperature.

scholarly journals Ferromagnetic Behaviors in Fe-Doped NiO Nanofibers Synthesized by Electrospinning Method

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Yi-Dong Luo ◽  
Yuan-Hua Lin ◽  
Xuehui Zhang ◽  
Deping Liu ◽  
Yang Shen ◽  
...  
Keyword(s):  
Room Temperature ◽  
Doping Concentration ◽  
Double Exchange ◽  
Host Lattice ◽  
Charge Carriers ◽  
Fe Doping ◽  
Free Charge ◽  
Ferromagnetic Properties ◽  
Electrospinning Method ◽  
Fe Ions

Ni1−xFexOnanofibers with different Fe doping concentration have been synthesized by electrospinning method. An analysis of the phase composition and microstructure shows that Fe doping has no influence on the crystal structure and morphology of NiO nanofibers, which reveals that the doped Fe ions have been incorporated into the NiO host lattice. Pure NiO without Fe doping is antiferromagnetic, yet all the Fe-doped NiO nanofiber samples show obvious room-temperature ferromagnetic properties. The saturation magnetization of the nanofibers can be enhanced with increasing Fe doping concentration, which can be ascribed to the double exchange mechanism through the doped Fe ions and free charge carriers. In addition, it was found that the diameter of nanofibers has significant impact on the ferromagnetic properties, which was discussed in detail.

Electronic and magnetic states of Fe ions in the Co2FeBO5

2021 ◽  
Author(s):  
Natalia Kazak ◽  
Yurii V. Knyazev ◽  
Vyacheslav Zhandun ◽  
Juan Bartolomé ◽  
Ana Arauzo ◽  
...  
Keyword(s):  
Mössbauer Spectroscopy ◽  
Room Temperature ◽  
Mössbauer Spectra ◽  
Mossbauer Spectroscopy ◽  
57Fe Mössbauer Spectroscopy ◽  
57Fe Mössbauer ◽  
Mossbauer Spectra ◽  
57Fe Mossbauer Spectroscopy ◽  
Magnetic States ◽  
Fe Ions

The ludwigite Co2FeBO5 has been studied experimentally using 57Fe Mössbauer spectroscopy and theoretically by means of the DFT+GGA calculations. The room-temperature Mössbauer spectra are composed of four quadrupole doublets corresponding...

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