Magnetic after-effect in amorphous Fe85 − xCrxB15 alloys

Vojtaník, P.; Varga, R.; Kravčák, J.; Lovas, A.

doi:10.1016/s0921-5093(96)10721-8

Cited by 5 publications

(5 citation statements)

References 8 publications

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“…Equations ( 3) can be expanded by introducing annealing jump frequencies ν ( p) A if the total number of TLSs decreases due to annealing. In that case n ( p) 0 in (6) has to be replaced by the expression n ( p)…”

Section: The Kinetics Of the Transitionsmentioning

confidence: 99%

“…The peak just below the Curie temperature is usually narrow, and originates from a ferromagnetic to paramagnetic phase transition. This description of a typical MAE spectrum holds for a wide variety of compositions, from binary (Co, Fe)-M, where M is a metalloid [2][3][4][5] through ternary and quaternary alloys [1,[6][7][8] to multicomponent systems [9]; hence some authors argue (see [10] and references therein) that the magnetic relaxation has a structural, rather than compositional nature.…”

Section: Introductionmentioning

confidence: 99%

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Directional ordering in amorphous Co–Si–B alloys

Andrejco¹,

Vojtaník²

2004

J. Phys.: Condens. Matter

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Directional ordering in the amorphous Co75Si15B10 alloys by means of the magnetic after-effect (MAE) of the initial reluctivity and its influence on the Perminvar effect have been investigated. Two peak MAE spectra were obtained from isochronal measurements for as-cast as well as annealed samples. The spectrum of the as-cast sample has peak maxima at 383 and 545 K. Comparing this MAE spectrum with the spectrum of amorphous Co75B25 alloy, we identified the first peak as a result of Co–B atom pair reorientation (B-type relaxation) and the second one at higher temperatures as a result of Co–Si atom pair reorientation (Si-type relaxation). After annealing, the peaks shift to 442 and 576 K, respectively. For the numerical analysis of Co75Si15B10 MAE spectra we modified the micromagnetic model assuming the existence of more relaxation processes, where each process is connected to the relaxation of one metalloid element. The pre-exponential factor for B-type relaxation was found to be τ0,AC(B) = 7 × 10−17 s with the most probable activation energy QAC*(B) = 1.31 eV. These values correlate very well with the magnetic relaxation (MR) activation parameters of Co75B25 alloy, τ0,AC = 2 × 10−17 s and QAC* = 1.35 eV. Si-type relaxation has activation parameters τ0,AC(Si) = 6 × 10−18 s and QAC*(Si) = 1.96 eV. After annealing the sample at 683 K for 30 min they change to values τ0,AN(B) = 2 × 10−15 s, QAN*(B) = 1.38 eV and τ0,AN(Si) = 3 × 10−17 s, QAN*(Si) = 2.01 eV. The complicated shapes of the long-time isotherms reflect the superposition of two relaxation processes. We have numerically split each isotherm into two sub-isotherms representing the particular contributions of the two relaxation processes. The MAE spectrum of the critical field measured on the as-cast sample also has two peaks, like the reluctivity spectrum. The impact of Co–B and Co–Si atom pairs on the behaviour of the domain wall stabilization potential is discussed for the explanation of the observed MR results.

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Section: The Kinetics Of the Transitionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Directional ordering in amorphous Co–Si–B alloys

Andrejco¹,

Vojtaník²

2004

J. Phys.: Condens. Matter

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“…The Mn alloying was used to produce amorphous wires with application potential as sensors [6]. Influence of the Cr alloying on the properties of Fe-based amorphous alloys was frequently investigated [7,8], but there is a lack of information connected to the influence of Cr alloying on the magnetic properties of Co-based alloys.…”

Section: Introductionmentioning

confidence: 99%

Magnetic and Structural Properties of Amorphous Co-Cr-Si-B Alloys

Vojtaník¹,

Andrejco²,

Varga³

et al. 2004

Czech J Phys

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Magnetic and structural properties of amorphous Co 80−x Cr x Si 6 B 14 , x=0, 2, 4, 6 and 8 at. %, alloys were investigated. Temperature dependences of saturation magnetizations and relative initial susceptibilities were compared with the temperature dependences of heat flow obtained by DSC technique. Two crystallization temperatures were obtained in the temperature range 300-870 K. First crystallization leads to the formation of magnetically harder ferromagnetic material. Second crystallization additionally increases magnetization of the samples with 0 and 2 at. % Cr and decreases it for higher Cr content. Concentration dependences of saturation magnetization, Curie as well as crystallization temperatures are reported. Increase of Cr contents decreases coercive fields of alloys. The influence of the under-critical annealing on the coercivity is discussed.PACS : 75.50.Kj

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“…The influence of Cr on the stability of Febased amorphous alloys was systematically studied in Refs. [8][9][10], but there is a lack of papers discussing influence of Cr on the stability of amorphous Co-based alloys.…”

Section: Introductionmentioning

confidence: 99%