scholarly journals Impact of Magneto-optical Properties Depending on the Orientation in the Plane of Cobalt Ferrite Locked in a Silica Matrix

2021 ◽  
pp. 46-50
Author(s):  
Nandiguim Lamaï ◽  
Désiré Allassem ◽  
Alexis Mouangué Nanimina ◽  
Djimako Bongo ◽  
Togdjim Jonas
Keyword(s):  
Optical Properties ◽  
Faraday Effect ◽  
Cobalt Ferrite ◽  
Magnetic Moments ◽  
Silica Matrix ◽  
Preferential Orientation ◽  
Solid Matrix ◽  
Magnetic Orientation

In this work, we discuss the magneto-optical properties according to the orientation of 15nm-sized cobalt ferrite blocked in a silica matrix in comparison to the study done on 20nm-sized cobalt ferrite. This measurement shows that it is possible to increase the remanence of the Faraday effect by creating a magnetic orientation in the solid matrix, which is interesting for the production of self-polarized components. In addition, this remanence is greater for 15 nm than for 20 nm.A gelation field applied perpendicular to the plane of the layer therefore produces a preferential orientation of the magnetic moments in the direction of the field applied during the measurement.

A caging strategy for tuning the magneto-optical properties of cobalt ferrite using a single plasmonic nanoparticle

2021 ◽  
Vol 9 (15) ◽  
pp. 5098-5104
Author(s):  
Martín Testa-Anta ◽  
Ana Sousa-Castillo ◽  
Alberto López-Ortega ◽  
Miguel A. Correa-Duarte ◽  
Antonio García-Martín ◽  
...  
Keyword(s):  
Optical Properties ◽  
Gold Nanoparticle ◽  
Faraday Effect ◽  
Cobalt Ferrite ◽  
Plasmonic Nanoparticle ◽  
Induced Changes

Investigations of the Faraday effect in silica capsules with numerous CoFe2O4 nanoparticles and one single gold nanoparticle demonstrate the plasmon-induced changes in the MOA of the ferrite and highlights the caging strategy designed.

scholarly journals Difference between Brownian and Néel relaxation mechanisms in a magnetizing field

2021 ◽  
pp. 14-20
Author(s):  
Alexander V. Lebedev ◽  
Keyword(s):  
Relaxation Time ◽  
Oleic Acid ◽  
High Frequency ◽  
Cobalt Ferrite ◽  
Magnetic Moments ◽  
Relaxation Mechanism ◽  
Dynamic Susceptibility ◽  
Magnetite Particles ◽  
Magnetizing Field ◽  
Néel Relaxation

Measurements of the dynamic susceptibility of a magnetic fluid based on cobalt ferrite particles stabilized in water by a double surfactant layer have been carried out. Cobalt ferrite, in comparison with magnetite, has a significantly higher energy of magnetic anisotropy. Therefore, for particles of cobalt ferrite, the Brownian mechanism of relaxation of magnetic moments is characteristic. The Debye (with a finite relaxation time) contribution to the dynamic susceptibility and the high-frequency (dispersionless) contribution are distinguished by constructing Cole-Cole diagrams. It was found that with an increase in the magnetizing field, the Debye contribution to the dynamic susceptibility decreases, while the high-frequency one (having a zero relaxation time) remains unchanged. The indicated property of the dynamic susceptibility of a fluid with a Brownian relaxation mechanism is radically different from the properties of the susceptibility of a fluid with Néel particles. Previously, measurements were made of the susceptibility of a fluid based on magnetite particles stabilized with oleic acid in kerosene. The magnetite particles have significantly lower anisotropy energy and are characterized by the predominance of the Néel relaxation mechanism. Turning on the magnetizing field caused a decrease in both the Debye part of the susceptibility and the high-frequency part of the susceptibility of magnetite particles.

DFT study of elastic, half-metallic and optical properties of Co2V(Al, Ge, Ga and Si) compounds

2017 ◽  
Vol 31 (14) ◽  
pp. 1750109 ◽  
Author(s):  
Heidar Khosravi ◽  
Arash Boochani ◽  
Golnaz Rasolian ◽  
Shahram Solaymani ◽  
Sirvan Naderi
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Magnetic Moments ◽  
Elastic Stability ◽  
Metallic Behavior ◽  
Functional Theory ◽  
Spin Mode ◽  
Half Metallic ◽  
Lattice Constants ◽  
Optical Treatment

First-principles study of elastic, electronic and optical properties of full-Heusler Co2V(Al, Ge, Ga and Si) compounds are calculated through density functional theory (DFT) to obtain and compare the mentioned properties. Equilibrium lattice constants of these compounds are in good agreement with other works. Electronic calculations are shown full spin polarization at Fermi level for all compounds, so in the down spin, indirect bandgap is calculated as 0.33, 0.6, 0.2 and 0.8 eV for Co2V(Al, Ge, Ga and Si), respectively. The integer amounts of the magnetic moments are compatible with Slater–Pauling role. The optical treatment of Co2VGa is different from three other compounds. All mentioned compounds have metallic behavior by 22 eV plasmonic frequency. The imaginary part of the dielectric function for the up spin indicates that the main optical transitions occurred in this spin mode. Moreover, the elastic results show that the Co2VGa does not have elastic stability, but the other three compounds have fully elastic stability and the Co2V(Al, Ge and Si) belong to the hardness of materials.

Optical properties of Rh6G:C337 dye mixture in the sol-gel silica matrix

2004 ◽  
Vol 39 (12) ◽  
pp. 4017-4019 ◽  
Author(s):  
Dae Wook Choi ◽  
Chun Woo Lim ◽  
Sang Ho Sohn
Keyword(s):  
Optical Properties ◽  
Sol Gel ◽  
Silica Matrix

Synthesis, characterisation and optical properties of nanocrystalline Y2O3–Eu3+dispersed in a silica matrix by a deposition–precipitation method

2003 ◽  
Vol 13 (12) ◽  
pp. 3079-3084 ◽  
Author(s):  
Carla Cannas ◽  
Mariano Casu ◽  
Marina Mainas ◽  
Anna Musinu ◽  
Giorgio Piccaluga ◽  
...  
Keyword(s):  
Optical Properties ◽  
Silica Matrix ◽  
Precipitation Method

scholarly journals Encapsulation of cationic iridium(iii) tetrazole complexes into a silica matrix: synthesis, characterization and optical properties

2018 ◽  
Vol 42 (12) ◽  
pp. 9635-9644 ◽  
Author(s):  
Ilaria Zanoni ◽  
Valentina Fiorini ◽  
Marcos Rosado ◽  
Belén Ballesteros ◽  
Maria Androulidaki ◽  
...  
Keyword(s):  
Optical Properties ◽  
Silica Matrix ◽  
Matrix Synthesis ◽  
Multi Scale ◽  
Molecular Scale

We designed a multi-scale process, and obtained luminescent powders with preserved optical properties from molecular scale to microscale.

scholarly journals Optical and magneto-optical properties of GdxFe(100-x) thin films close to the compensation point

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Eva Jesenská ◽  
Takayuki Ishibashi ◽  
Lukáš Beran ◽  
Martin Pavelka ◽  
Jaroslav Hamrle ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Spectral Dependence ◽  
Room Temperature ◽  
Magnetic Moments ◽  
Perpendicular Magnetic Anisotropy ◽  
Theoretical Models ◽  
Compensation Point ◽  
Spin Torque ◽  
Dc Sputtering

Abstract Unlike ferromagnetic materials, ferrimagnetic metals have recently received considerable attention due to their bulk perpendicular magnetic anisotropy, low net magnetization and tunable magnetic properties. This makes them perfect candidates for the research of recently discovered spin-torque related phenomena. Among other ferrimagnetic metals, GdFe has an advantage in relatively large magnetic moments in both sublattices and tunability of compensation point above the room temperature by small changes in its composition. We present a systematic study of optical and magneto-optical properties of amorphous GdxFe(100-x) thin films of various compositions (x = 18.3, 20.0, 24.7, 26.7) prepared by DC sputtering on thermally oxidized SiO2 substrates. A combination of spectroscopic ellipsometry and magneto-optical spectroscopy in the photon energy range from 1.5 to 5.5 eV with advanced theoretical models allowed us to deduce the spectral dependence of complete permittivity tensors across the compensation point. Such information is important for further optical detection of spin related phenomena driven by vicinity of compensation point in nanostructures containing GdFe.

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