High-Field Magnetoresistance of Magnetic Nanocomposites near the Percolation Threshold

We present results of experimental studies of high-field magnetoresistance of Co–SiO 2 , Co–LiNbO 3 , CoNbTa–SiO 2 nanocomposites with metal volume fraction close to the percolation threshold. The nanocomposite films were deposited onto a glass-ceramic substrate by ion-beam sputtering at the growth...

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Bibliographic Details
Published in:Journal of experimental and theoretical physics 2021-12, Vol.133 (6), p.771-778
Main Authors: Fadeev, E. A., Shakhov, M. A., Lähderanta, E., Taldenkov, A. N., Vasiliev, A. L., Sitnikov, A. V., Rylkov, V. V., Granovsky, A. B.
Format: Article
Language:English
Subjects:
Anisotropy
Classical and Quantum Gravitation
Disorder
Elementary Particles
Glass ceramics
Glass substrates
Ion beam sputtering
Lithium niobates
Magnetic fields
Magnetism
Magnetization
Magnetometers
Magnetoresistance
Magnetoresistivity
Nanocomposites
Order
Particle and Nuclear Physics
Percolation
Phase Transition in Condensed System
Physics
Physics and Astronomy
Pulse duration
Quantum Field Theory
Relativity Theory
Silicon dioxide
Solid State Physics
Superconducting quantum interference devices
Superconductors
Zeeman effect
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Summary:We present results of experimental studies of high-field magnetoresistance of Co–SiO 2 , Co–LiNbO 3 , CoNbTa–SiO 2 nanocomposites with metal volume fraction close to the percolation threshold. The nanocomposite films were deposited onto a glass-ceramic substrate by ion-beam sputtering at the growth temperature not exceeding 80°C. Magnetization was measured using a superconducting quantum interference device (SQUID) magnetometer in the temperature range of 4.2–300 K. Out-of-plane magnetoresistance was measured in a pulsed magnetic field up to 20 T in the temperature range of 4.2–300 K with the pulse duration of 11–12 ms. In addition to negative magnetoresistance, a linear positive contribution to magnetoresistance was observed in high magnetic fields for nanocomposites with the composition close to the percolation threshold. This effect was explained by the influence of the Zeeman effect on the tunnel barrier height. It is shown that the unconventional anisotropy of magnetoresistance of Co–LiNbO 3 is associated with the peculiarities of its microstructure.
ISSN:1063-7761
1090-6509
DOI:10.1134/S1063776121120049