Soft matter, sol–gel process and external magnetic field to design macrocellular silica scaffolds

2005 ◽  
Vol 263 (1-3) ◽  
pp. 341-346 ◽  
Author(s):  
Florent Carn ◽  
Annie Colin ◽  
Véronique Schmitt ◽  
Fernando Leal Calderon ◽  
Rénal Backov
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Soft Matter ◽  
Sol Gel ◽  
Sol Gel Process

Spectral selectivity of 3D magnetophotonic crystal film fabricated from single butterfly wing scales

Nanoscale ◽  
2014 ◽  
Vol 6 (11) ◽  
pp. 6133-6140 ◽  
Author(s):  
Wenhong Peng ◽  
Shenmin Zhu ◽  
Wang Zhang ◽  
Qingqing Yang ◽  
Di Zhang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Sol Gel ◽  
Butterfly Wing ◽  
Spectral Selectivity ◽  
Crystal Film ◽  
Sol Gel Process ◽  
Magnetophotonic Crystal ◽  
Wing Scales ◽  
Magnetite Film

A magnetite film with photonic structures, which possess spatial optical anisotropy properties and can be tuned by an external magnetic field, has been successfully fabricated by a simple sol–gel process.

Effects of Ca2+-Doping on the Crystal Lattice of α-Fe2O3

2014 ◽  
Vol 975 ◽  
pp. 116-121
Author(s):  
Bruna da Costa Andrade ◽  
José Cleverton da Conceição Passos ◽  
Marcelo Andrade Macedo
Keyword(s):  
Magnetic Field ◽  
Electrical Resistivity ◽  
Crystal Lattice ◽  
Coercive Field ◽  
Calcium Concentration ◽  
Sol Gel ◽  
Impedance Analysis ◽  
Hematite Phase ◽  
Sol Gel Process ◽  
The Magnetic Field

Samples of CayFe12-yO19 (0 ≤ y ≤ 1.0) were prepared by a proteic sol–gel process with hematite phase and clusters of M-type calcium hexaferrite. Impedance analysis showed that the resistivity increased with calcium concentration in the 0.0 < y ≤ 0.2 range, but decreased for y > 0.2. The saturation of the electrical resistivity occurred at 7.5 × 106 Ω·cm for Ca0.9Fe11.1O19. The plot of magnetization as a function of the magnetic field showed high values of saturation magnetization (40 emu/g) with low remanence (6.7 emu/g) and coercive field (320 Oe).

scholarly journals Self-standing magnetic composite nanosheets prepared in the presence of an external magnetic field: Characterization and potential for medical applications

2020 ◽  
pp. 174751982095860
Author(s):  
Mina Sakuragi ◽  
Yoshikazu Takahashi ◽  
Keito Ehara ◽  
Katsuki Kusakabe
Keyword(s):  
Magnetic Field ◽  
Thermal Decomposition ◽  
External Magnetic Field ◽  
Decomposition Method ◽  
Sol Gel ◽  
Magnetic Composite ◽  
Magnetic Response ◽  
Gel Method ◽  
Sol Gel Method ◽  
Thermal Decomposition Method

The aim of this study is to develop self-standing, ultrathin film, nanosheets with high magnetic response for use in a medical device that can be migrated to a target location in the body by using an external magnetic field. First, iron oxide nanoparticles are synthesized by either the sol-gel method or thermal decomposition. The resulting magnetic properties of the nanoparticles show that the thermal decomposition method provides a greater saturation magnetization value than the sol-gel method. Next, the nanoparticles obtained by the thermal decomposition method are embedded into nanosheets of poly(L-lactide) at varying concentrations. Embedding of the nanoparticles in the composite nanosheets is achieved by the application of an external magnetic field. The composite nanosheets are then characterized. The thickness of the nanosheet increases, and the nanoparticles are well dispersed, with an increase in poly (L-lactide) concentration. The NP-embedded nanosheets are imaged by transmission electron microscopy, which reveals thin, long aggregates aligned in collinear line features. X-ray diffraction results indicate that the magnetic hard axis of the nanoparticles in the nanosheets is aligned in parallel to the plane of the nanosheet by magnetic field application during nanosheet preparation. In addition, the nanosheets at high poly (L-lactide) concentrations that had been subjected to a magnetic field during preparation show a slightly greater magnetic response compared with both nanosheets without magnetic field exposure and nanosheets prepared at low poly (L-lactide) concentrations.

scholarly journals Structural, Magnetic and Microwave Characterization of Polycrystalline Z-Type Sr3Co2Fe24O41 Hexaferrite

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2355
Author(s):  
Svetoslav Kolev ◽  
Petya Peneva ◽  
Kiril Krezhov ◽  
Tanya Malakova ◽  
Chavdar Ghelev ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Sol Gel ◽  
Peak Frequency ◽  
Magnetic Phase Transitions ◽  
Microwave Properties ◽  
Zero Field ◽  
Auto Combustion ◽  
Dramatic Rise ◽  
Absorbing Material

We report results on the structural and microwave properties and magnetic phase transitions in polycrystalline Sr3Co2Fe24O41 hexaferrite synthesized by sol-gel auto-combustion and acting as a filler in a composite microwave absorbing material. The zero-field-cooled (ZFC) and field-cooled (FC) magnetization curves revealed a change in the magnetization behavior at 293 K. The reflection losses in the 1–20 GHz range of the Sr3Co2Fe24O41 powder dispersed homogeneously in a polymer matrix of silicon rubber were investigated in both the absence and presence of a magnetic field. In the latter case, a dramatic rise in the attenuation was observed. The microwave reflection losses reached the maximum value of 32.63 dB at 17.29 GHz in the Ku-band. The sensitivity of the microwave properties of the composite material to the external magnetic field was manifested by the appearance of new reflection losses maxima. At a fixed thickness tm of the composite, the attenuation peak frequency can be adjusted to a certain value either by changing the filling density or by applying an external magnetic field.

Macrocellular Silica Monoliths Hierarchically Textured: Mesostructured Si-HIPE Materials

2004 ◽  
Vol 847 ◽  
Author(s):  
F. Carn ◽  
A. Colin ◽  
R. Backov
Keyword(s):  
Soft Matter ◽  
Volume Fraction ◽  
Sol Gel ◽  
General Context ◽  
New Materials ◽  
Silica Monoliths ◽  
Sol Gel Process ◽  
Ph Conditions ◽  
Nice Tool ◽  
Concentrated Emulsion

ABSTRACTInterface between sol-gel process and soft matter appears recently as a very nice tool to generate new materials with complex textures or/and structures extended at various length scales. In this general context, hierarchical inorganic porous monoliths have been prepared using a double templates procedure, namely concentrated emulsion as a macroscopic pattern and mesoscopic micellar templates. The texture of those monoliths can vary dramatically playing either with the oil volume fraction, synthetic pH conditions or the emulsification process. These materials show interconnected macroporosity associated to vermicular-type mesostructuration with an average mesoporosity of 800 m2/g associated to bulk density as low as 0.08 g cm-3 which is comparable to values obtained for silica aerogel.

The crystallization of thin-film ceramics

1992 ◽  
Vol 50 (1) ◽  
pp. 338-339
Author(s):  
J.M. Schwartz ◽  
L.F. Francis ◽  
L.D. Schmidt ◽  
P.S. Schabes-Retchkiman
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Sol Gel ◽  
Processing Route ◽  
Small Areas ◽  
Ceramic Thin Films ◽  
Complex Shapes ◽  
Sol Gel Process ◽  
Ceramic Precursors ◽  
Crystalline Ceramic

Ceramic thin films and coatings are of interest for electrical, optical, magnetic and thermal barrier applications. Critical for improved properties in thin films is the development of specific microstructures during processing. To this end, the sol-gel method is advantageous as a versatile processing route. The sol-gel process involves depositing a solution containing metalorganic or colloidal ceramic precursors onto a substrate and heating the deposited layer to form a crystalline or non-crystalline ceramic coating. This route has several advantages, including the ability to create tailored microstructures and properties, to coat large or small areas, simple or complex shapes, and to more easily prepare multicomponent ceramics. Sol-gel derived coatings are amorphous in the as-deposited state and develop their crystalline structure and microstructure during heat-treatment. We are particularly interested in studying the amorphous to crystalline transformation, because many key features of the microstructure such as grain size and grain size distribution may be linked to this transformation.

RECOIL IMPLANTATION MÖSSBAUER EXPERIMENT ON 57Fe IN Ge IN THE PRESENCE OF AN EXTERNAL MAGNETIC FIELD

1980 ◽  
Vol 41 (C1) ◽  
pp. C1-445-C1-445
Author(s):  
G. Langouche ◽  
N. S. Dixon ◽  
L. Gettner ◽  
S. S. Hanna
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Recoil Implantation
Sign in / Sign up

Export Citation Format

Share Document