The effect of helical magnetoelastic anisotropy on magnetoimpedance and its second harmonic component in amorphous wires

Duque, Juan G.; Gómez‐Polo, C.; Yelon, A.; Ciureanu, P.; Araújo, Aruzza Mabel de Morais; Knobel, M.

doi:10.1016/j.jmmm.2003.10.005

Cited by 32 publications

(37 citation statements)

References 21 publications

(32 reference statements)

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“…7 Among various nonlinear phenomena, "frequency multiplication" ͑higher order harmonics of GMI signal͒ has already been investigated. [8][9][10][11][12][13][14][15] Although the similarity between the experimental configurations for transverse GMI in metallic ribbons and parallel pumping experiments in ferromagnetic insulators has already been pointed out by Yelon et al, 7 the parametric excitation of spin waves, 16 and other known nonlinear phenomena have not been reported so far.The aim of this paper is to show that spatially inhomogeneous magnetic excitations can be pumped in the usual "low power" GMI microwave experiments. To demonstrate this, GMI has been measured in magnetically soft glass coated microwires which are known to exhibit quite outstanding magnetic properties, including GMI.…”

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confidence: 84%

Nonlinear magnetoimpedance and parametric excitation of standing spin waves in a glass-covered microwire

et al. 2009

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The giant magnetoimpedance of an 8.5 m glass-covered amorphous microwire was investigated in the frequency range of 10 MHz-3.5 GHz. It was found that when the exciting microwave current exceeds some threshold value, a periodic fine structure appears in the frequency dependence of the complex impedance. The appearance of this nonlinear phenomenon is interpreted to be a consequence of the parametric excitation of standing spin waves. © 2009 American Institute of Physics. ͓DOI: 10.1063/1.3079659͔ Nonlinear magnetization dynamics, which is one of the fundamental issues in applied magnetism, has recently received increasing attention in connection with the advances in magnetic storage technologies and spintronics. 1 Materials and devices used in these areas typically have nanoscale dimensions and operate in the gigahertz range. The understanding of magnetization dynamics is of great importance for these technologies. The nonlinear behavior of ferrites and garnets was systematically investigated during the 1950s and 1960s, particularly in connection with the development of radar and microwave techniques. With increasing interest in metallic ferromagnets, nowadays, new experimental methods are desirable for investigation of the nonlinear magnetic phenomena in these materials. One such technique is the giant magnetoimpedance ͑GMI͒.GMI comes from the dependence of electromagnetic skin depth in soft magnetic metals on the external dc magnetic field. 2 It has been shown by Yelon et al. 3 that the theoretical description of GMI, which is based on the simultaneous solution of Maxwell equations and the LandauLifshitz ͑LL͒ equation of motion is similar to the theory of ferromagnetic resonance ͑FMR͒ in metals. The LL is generally a nonlinear equation. In the small signal limit ͑low ac excitation current͒, where the LL equation can be linearized, this theoretical approach provides a very good explanation for the observed GMI behavior. 4 Nevertheless, at high excitation current, where the nonlinearity of LL equation must be taken into account, nonlinear effects should appear. Considering the correspondence between GMI and FMR one can expect that various nonlinear effects, similar to those observed in FMR, 5 also take place in the GMI. Because of the large damping of magnetization motion, the standard nonlinear FMR experiments in ferromagnetic metals require high power microwave sources. 6 In GMI measurements, however, the conditions for nonlinear behavior can already be achieved with exciting currents of a few milliampere. 7 Among various nonlinear phenomena, "frequency multiplication" ͑higher order harmonics of GMI signal͒ has already been investigated. [8][9][10][11][12][13][14][15] Although the similarity between the experimental configurations for transverse GMI in metallic ribbons and parallel pumping experiments in ferromagnetic insulators has already been pointed out by Yelon et al., 7 the parametric excitation of spin waves, 16 and other known nonlinear phenomena have not been reported so far.The aim of this paper is to ...

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confidence: 84%

Nonlinear magnetoimpedance and parametric excitation of standing spin waves in a glass-covered microwire

et al. 2009

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“…The appearance of the asymmetry in one of the branches and not in the other could be related to the helix orientation of the induced anisotropy. The asymmetry produced in circular magnetization processes by the torsional stresses has also been observed in Co-rich fibres [10] and an theoretical explanation can also be found in Co-rich wires [6].…”

Section: Resultsmentioning

confidence: 67%

Torsion and magnetic field effect in the impedance of FeSiBNbCu soft magnetic amorphous wires

Sánchez

Hernando

Olivera

et al. 2006

Journal of Magnetism and Magnetic Materials

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“…High-frequency MI and FMR have led to some confusion in the past [16,17]; however, we feel that the differences between FMR and MI are now well established. Recent results show [18] that as frequency increases (in the 200 MHz -6 GHz range for Co-rich amorphous ribbons), a divergence in the MI response appears with two maxima in the impedance response, corresponding to ±H K (the value of which remains virtually constant at all frequencies), and the FMR response, which becomes field dependent, with a Larmor relation that depends on the geometry of the sample.…”

Section: Experimental Results and Modelingmentioning

confidence: 91%

Effect of the metal-to-wire ratio on the high-frequency magnetoimpedance of glass-coated CoFeBSi amorphous microwires

Valenzuela

Fessant²,

Gieraltowski³

et al. 2008

Sensors and Actuators A: Physical

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High frequency [1-500 MHz] measurements of the magnetoimpedance (MI) of glass-coated Co69.4Fe3.7B15.9Si11 microwires are carried out with various metal-to-wire diameter ratios. A twinpeak, anhysteretic behaviour is observed as a function of magnetic field. A maximum in the normalized impedance, ∆Z/Z, appears at different values of the frequency f , 125, 140 and 85 MHz with the corresponding diameter ratio p = 0.80, 0.55 and 0.32. We describe the measurement technique and interpret our results with a thermodynamic model that leads to a clearer view of the effects of p on the maximum value of MI and the anisotropy field. The behavior of the real and imaginary components of impedance is also investigated; they display a resonance that becomes a function of the DC field HDC for values larger or equal to HK the circumferential anisotropy field for each p value. These results are interpreted in terms of a rotation model of the outer shell magnetization.

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The effect of helical magnetoelastic anisotropy on magnetoimpedance and its second harmonic component in amorphous wires

Cited by 32 publications

References 21 publications

Nonlinear magnetoimpedance and parametric excitation of standing spin waves in a glass-covered microwire

Nonlinear magnetoimpedance and parametric excitation of standing spin waves in a glass-covered microwire

Torsion and magnetic field effect in the impedance of FeSiBNbCu soft magnetic amorphous wires

Effect of the metal-to-wire ratio on the high-frequency magnetoimpedance of glass-coated CoFeBSi amorphous microwires

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