The phenomenon of magnetic exchange bias in ferromagnetic nanocomposites grown by electron beam evaporation

Radchenko, M. V.

doi:10.15407/spqeo21.02.125

Cited by 3 publications

(2 citation statements)

References 7 publications

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“…The behavior of the magnetothermoelectric power in Сo/SiO 2 can be explained taking into account that in addition to the spin‐dependent hopping conductivity due to the elastic tunneling of electrons between the nanoparticles we also have hopping conductivity via single Co atoms, nanoscale antiferromagnetic CoO and ferromagnetic CoSi, Co 3 Si silicides …”

Section: Resultsmentioning

confidence: 99%

Electronic Transport and Magnetic Properties of Co/SiO₂Magnetic Nanocomposites

Radchenko

Lashkarev

Baibara

et al. 2019

Physica Status Solidi (b)

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Electric, thermoelectric, and magnetic properties of the magnetic nanocomposite (MNC) Co/SiO2 consisting of nanometer‐size Co nanoparticles embedded in SiO2 dielectric matrix have been studied. MNC is obtained in the form of (0.8–2.3) μm thick films with Co concentration 31.7–65.4 at.% by the electron beam physical vapor deposition method on polycrystalline Al2O3 substrates. The temperature dependence of the resistivity follows the Mott law. The negative magnetothermoelectric power discovered in MNC Co/SiO2 can be explained by hopping conductivity through the magnetic localization centers in the SiO2 matrix or chemical interaction of Co with Si and O2, which results in a mixture of CoSi (ferromagnetic) and CoO (antiferromagnetic) phases. As the cobalt concentration increases, the particle size increases and the interparticle distances decrease. This is confirmed by the magnetic behavior of the sample with high Co concentration, which is dominated by large Co nanoparticles and strong interparticle magnetic interactions.

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Section: Resultsmentioning

confidence: 99%

Electronic Transport and Magnetic Properties of Co/SiO₂Magnetic Nanocomposites

Radchenko

Lashkarev

Baibara

et al. 2019

Physica Status Solidi (b)

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“…The application of various types of such materials (granular nanostructures, cermets, vacuum tunnel junctions, etc.) allows expanding the frontiers of their practical application [5][6][7][8]. For example, with combined ferromagnetic and non-magnetic materials, we can form structures with high saturation magnetization at high thermal stability.…”

Section: Introductionmentioning

confidence: 99%

Peculiarity of Magnetoresistance of Composite Materials Based on Co and SiO

Pazukha¹,

Shchotkin²,

Pylypenko³

et al. 2021

J. Nano- Electron. Phys.

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A series of thin-film composite materials based on Co and SiO were deposited via electron-beam coevaporation technique using two independent sources. The concentration of Co atoms of thin-film composite materials varied from 35 to 90 at. %. It was controlled by using a scanning electron microscope (Tescan VE-GA3) with an energy-scattering X-ray (EDX) detector (Oxford Instruments). The total thickness of the nanocomposites was controlled by a system of two independent quartz resonators and amounted to 30 and 60 nm. The magnetoresistive properties of these structures deposited at room temperature were investigated. The results showed that the percolation threshold for the system based on Co and SiO is in the concentration range of сСо  60-70 at. %. From the field dependences of the magnetoresistance (MR) obtained at room temperature, it follows that the electrical resistance of the films decreases when they are introduced into the magnetic field (negative magnetoresistance). The negative MR indicates that the dominant effect observed is due to spin-dependent electron tunneling between ferromagnetic nanogranules. At the concentration range of сСо  40-60 at. %, isotropic MR of 1.5-2.5 % is realized. The maximum on the concentration dependences of MR shifts to the region of lower concentrations of Co with increasing sample thickness.

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Nontrivial Phenomena in Magnetic Nanocomposites Co/Al2O3 and Co/SiO2

Lashkarev

Radchenko

Baibara

et al. 2019

Low Temperature Physics

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Magnetic nanocomposites (MNC), in which nanoparticles of ferromagnetic metals are distributed in wide-gap dielectric matrices (Al2O3 or SiO2), are prospective materials for electronics due to their amenability to technological control of the concentration and size of ferromagnetic nanoparticles. Co/Al2O3 and Co/SiO2 MNC layers with Co concentrations below the percolation threshold were deposited on polycor substrates using electron-beam deposition in a vacuum (EB-PVD). Scanning electron microscopy showed the presence of tightly packed Co grains of irregular shape with sizes of 5–50 nm in MNC. Low-temperature measurements of the magnetization for MNC Co/Al2O3 were made in the temperature range 4–300 K and magnetic fields up to 10 kOe. The ‘magnetic exchange bias’ has been detected, and it increases with a rise in Co concentration. By studying the electrical properties of the MNC Co/Al2O3 and Co/SiO2 in the temperature range of 77–280 K, the Mott type electron transport hopping mechanism was established. We first observed the effect of a giant positive thermoelectric power in a magnetic field in MNC Co/Al2O3 and the effect of a negative magnetothermoelectric power in a Co/SiO2.

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The phenomenon of magnetic exchange bias in ferromagnetic nanocomposites grown by electron beam evaporation

Cited by 3 publications

References 7 publications

Electronic Transport and Magnetic Properties of Co/SiO₂Magnetic Nanocomposites

Electronic Transport and Magnetic Properties of Co/SiO₂Magnetic Nanocomposites

Peculiarity of Magnetoresistance of Composite Materials Based on Co and SiO

Nontrivial Phenomena in Magnetic Nanocomposites Co/Al2O3 and Co/SiO2

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The phenomenon of magnetic exchange bias in ferromagnetic nanocomposites grown by electron beam evaporation

Cited by 3 publications

References 7 publications

Electronic Transport and Magnetic Properties of Co/SiO2Magnetic Nanocomposites

Electronic Transport and Magnetic Properties of Co/SiO2Magnetic Nanocomposites

Peculiarity of Magnetoresistance of Composite Materials Based on Co and SiO

Nontrivial Phenomena in Magnetic Nanocomposites Co/Al2O3 and Co/SiO2

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Electronic Transport and Magnetic Properties of Co/SiO₂Magnetic Nanocomposites

Electronic Transport and Magnetic Properties of Co/SiO₂Magnetic Nanocomposites