Impedance and magnetization of CoFeZr nanoclusters embedded into alumina matrix

Saad, A.; Fedotov, А.К.; Свито, И. А.; Fedotova, J.; Andrievsky, B.V.; Kalinin, Yu. E.; Patryn, Aleksy; Федотова, В. В.; Malyutina-Bronskaya, V. V.; Mazanik, A.V.; Ситников, А. В.

doi:10.1016/j.jallcom.2005.12.115

Cited by 19 publications

(46 citation statements)

References 12 publications

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“…As follows from [3], the observed negative sign of dσ/ dT points to the dielectric regime of the electron transport at x < x C . Our previous experiments [1,2,4] showed that this is due to the realization of the thermally stimulated tunnelling of electrons over the dielectric barriers created by the alumina matrix and FeCoZr-oxide shells surrounding the metallic nanoparticles.…”

Section: Introductionmentioning

confidence: 95%

“…In our previous papers we studied a real part of the admittance σ of the (Fe 0.45 Co 0.45 Zr 0.10 ) x (Al 2 O 3 ) 1−x nanocomposite samples containing FeCoZr nanoparticles in the alumina matrix and deposited in Ar+O 2 gas mixture by ion-beam sputtering of complex targets containing metallic alloy and alumina stripes [1,2]. It was established that below the percolation threshold the studied composites were characterized by low values of σ.…”

Section: Introductionmentioning

confidence: 99%

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Formation of Noncoil-Like Inductance in Nanocomposites (Fe_0.45Co_0.45Zr_0.10)_x(Al₂O₃)_1-xManufactured by Ion-Beam Sputtering of Complex Targets in Ar+O₂Atmosphere

et al. 2011

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This paper investigates the inductive contribution to AC conductance in the granular nanocomposites (Fe0.45Co0.45Zr0.10)x(Al2O3)1−x. The initial nanocomposites studied were manufactured in Ar+O2 atmosphere by ion-beam sputtering of the target containing Fe0.45Co0.45Zr0.10 and alumina stripes and then subjected to the annealing procedure in air over the temperature range 373 K < Ta < 873 K. These samples, before and after annealing, were studied using the temperature 77 K < Tp < 300 K and frequency 50 Hz < f < 1 MHz dependences of a real part of the admittance σ(T, f ). Analysis of the observed σ(f, T p ) dependences for x < 0.5 demonstrated that in the studied samples the equivalent circuits with the capacitive and noncoil-like inductive contributions can be accomplished. Just in this case, the capacitive properties of RLC circuit with the phase angle −90• ≤ θ L < 0• are exhibited at low frequencies and the inductive properties with 0• become apparent at high frequencies. A value of the critical frequency f R , where θ H changes sign, depends on the metallic phase concentration x, measuring temperature T p , and annealing temperature T a .

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Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Formation of Noncoil-Like Inductance in Nanocomposites (Fe_0.45Co_0.45Zr_0.10)_x(Al₂O₃)_1-xManufactured by Ion-Beam Sputtering of Complex Targets in Ar+O₂Atmosphere

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“…All the technological procedures and experimental techniques are described in [2][3][4]. The used method makes it possible to obtain a variety of samples under identical conditions but with different metallic phase concentrations ranging 30 at.% < x < 65 at.%.…”

Section: Methodsmentioning

confidence: 99%

“…Our AC conductivity measurements were carried out with the same samples as for the measurements of direct current (DC) conductance, phase composition and magnetic state described in [2][3][4]. The previous measurements showed that the x C value was close to 45-47 at.% [2].…”

Section: Methodsmentioning

confidence: 99%

“…Also, it should be noted that the majority of the electric, magnetic, and other properties of such binary nanocomposites are mostly influenced by the external effects just at x values approaching the percolation threshold x C [2][3][4]. This feature makes these nanocomposites very attractive to the producers of various sensors, detectors, etc.…”

Section: Introductionmentioning

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The Features of Real Part of Admittance in the Nanocomposites (Fe₄₅Co₄₅Zr₁₀)_x(Al₂O₃)_{100 - x}Manufactured by the Ion-Beam Sputtering Technique with Ar Ions

et al. 2011

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The temperature and frequency dependences of the admittance real part σ(T, f ) in granular (Fe 45 Co 45 Zr 10 ) x (Al 2 O 3 ) 100−x nanocomposite films around the percolation threshold x C were investigated. The behaviour of σ(T, f ) vs. the temperature and frequency over the ranges 77-300 K and 50 Hz-1 MHz, respectively, displays the predominance of an activation (hopping) conductance mechanism for the samples below the percolation threshold x C and of a metallic one beyond the x C determined as 54 ± 2 at.%. The mean hopping range d for the nanoparticles diameter D was estimated at different metallic phase content x.

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Characterization of (Co_0.45Fe_0.45Zr_0.10)_x(Al₂O₃)_1–xnanocomposite films applicable as spintronic materials

Saad

Fedotov

Fedotova

et al. 2006

Phys. Status Solidi (c)

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The combined use of scanning electron microscopy, Mössbauer spectrometry, X‐ray diffraction and also DC/AC electrical and magnetic characterization techniques allowed this work to elucidate the influence of metal‐to‐dielectric component ration, and effect of oxygen in gas mixture on phase structure and properties of the Co0.45Fe0.45Zr0.10 ferromagnetic nanoparticles in amorphous dielectric Al2O3 matrix. The films of 3–5 µm thickness with compositions of 30 at.% < X < 60 at.% were sputtered on a single substrate from the compound target in the chamber containing either pure Ar or Ar‐O gas mixture. The films sputtered in Ar‐O mixture resulted in partial oxidation of metallic nanoparticles causing the shift of percolation threshold X c to 55 at.% as compared to 45–47 at.% for the samples deposited in pure Ar. Mössbauer studies of the films sputtered in Ar gas have shown that at X < X c metallic nanoparticles were at superparamagnetic state but for X > X c metallic phase showed a ferromagnetic behavior. DC carrier transport at the temperatures of 77–350 K were explained by hopping mechanisms and described by Mott and Shklowski‐Efros laws. That was also confirmed by the relationship power law of Z ′(f ) ∼ f –s (s ≤ 2) for real part of impedance at low temperatures (<120 K) for the samples on dielectric side of MIT. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Impedance and magnetization of CoFeZr nanoclusters embedded into alumina matrix

Cited by 19 publications

References 12 publications

Formation of Noncoil-Like Inductance in Nanocomposites (Fe_0.45Co_0.45Zr_0.10)_x(Al₂O₃)_1-xManufactured by Ion-Beam Sputtering of Complex Targets in Ar+O₂Atmosphere

Formation of Noncoil-Like Inductance in Nanocomposites (Fe_0.45Co_0.45Zr_0.10)_x(Al₂O₃)_1-xManufactured by Ion-Beam Sputtering of Complex Targets in Ar+O₂Atmosphere

The Features of Real Part of Admittance in the Nanocomposites (Fe₄₅Co₄₅Zr₁₀)_x(Al₂O₃)_{100 - x}Manufactured by the Ion-Beam Sputtering Technique with Ar Ions

Characterization of (Co_0.45Fe_0.45Zr_0.10)_x(Al₂O₃)_1–xnanocomposite films applicable as spintronic materials

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Impedance and magnetization of CoFeZr nanoclusters embedded into alumina matrix

Cited by 19 publications

References 12 publications

Formation of Noncoil-Like Inductance in Nanocomposites (Fe0.45Co0.45Zr0.10)x(Al2O3)1-xManufactured by Ion-Beam Sputtering of Complex Targets in Ar+O2Atmosphere

Formation of Noncoil-Like Inductance in Nanocomposites (Fe0.45Co0.45Zr0.10)x(Al2O3)1-xManufactured by Ion-Beam Sputtering of Complex Targets in Ar+O2Atmosphere

The Features of Real Part of Admittance in the Nanocomposites (Fe45Co45Zr10)x(Al2O3)100 - xManufactured by the Ion-Beam Sputtering Technique with Ar Ions

Characterization of (Co0.45Fe0.45Zr0.10)x(Al2O3)1–x nanocomposite films applicable as spintronic materials

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Formation of Noncoil-Like Inductance in Nanocomposites (Fe_0.45Co_0.45Zr_0.10)_x(Al₂O₃)_1-xManufactured by Ion-Beam Sputtering of Complex Targets in Ar+O₂Atmosphere

Formation of Noncoil-Like Inductance in Nanocomposites (Fe_0.45Co_0.45Zr_0.10)_x(Al₂O₃)_1-xManufactured by Ion-Beam Sputtering of Complex Targets in Ar+O₂Atmosphere

The Features of Real Part of Admittance in the Nanocomposites (Fe₄₅Co₄₅Zr₁₀)_x(Al₂O₃)_{100 - x}Manufactured by the Ion-Beam Sputtering Technique with Ar Ions

Characterization of (Co_0.45Fe_0.45Zr_0.10)_x(Al₂O₃)_1–xnanocomposite films applicable as spintronic materials