High frequency magnetoimpedance in Ni81Fe19/Fe50Mn50 exchange biased multilayer

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The magnetoimpedance effect is a versatile tool to investigate ferromagnetic materials, revealing aspects on the fundamental physics associated to magnetization dynamics, broadband magnetic properties, important issues for current and emerging technological applications for magnetic sensors, as well as insights on ferromagnetic resonance effect at non-saturated magnetic states. Here, we perform a theoretical and experimental investigation of the magnetoimpedance effect for the thin film geometry in a wide frequency range. We calculate the longitudinal magnetoimpedance for single layered, multilayered or exchange biased systems from an approach that considers a magnetic permeability model for planar geometry and the appropriate magnetic free energy density for each structure. From numerical calculations and experimental results found in literature, we analyze the magnetoimpedance behavior, and discuss the main features and advantages of each structure. To test the robustness of the approach, we directly compare theoretical results with experimental magnetoimpedance measurements obtained in a wide range of frequencies for an exchange biased multilayered film. Thus, we provide experimental evidence to confirm the validity of the theoretical approach employed to describe the magnetoimpedance in ferromagnetic films, revealed by the good agreement between numerical calculations and experimental results.

Section: E Exchange Biased Systemmentioning

confidence: 99%

“…Experimentally, studies on MI have been widely performed in sheets 9 , magnetic ribbons 10-15 , wires [16][17][18][19][20][21][22][23] , and in ferromagnetic films with several structures, such as single layered [24][25][26] , multilayered 2,27-33 , and structured multilayered samples [28][29][30][33][34][35][36][37][38][39] .…”

Section: Introductionmentioning

confidence: 99%

Magnetoimpedance effect at the high frequency range for the thin film geometry: Numerical calculation and experiment

Corrêa

Bohn

Silva

et al. 2014

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“…On the other hand, just a few studies compare numerical calculations and experimental results, probably due to the fact that the determination of the appropriate magnetic free energy density can represent a hard task. In particular, some successful examples reside in the employment of the anisotropic SW model to study the influence of the magnetic anisotropy on the properties of sintered magnets composed by SmCo 5 and Co [20,21], to describe transverse susceptibility of FeCoV thin films [25], and to investigate the magnetoimpedance effect in ferromagnetic films [42][43][44].…”

Section: Theoretical Approachmentioning

confidence: 99%

Quantifying magnetic anisotropy dispersion: Theoretical and experimental study of the magnetic properties of anisotropic FeCuNbSiB ferromagnetic films

Alves

Bezerra

Viegas

et al. 2015

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The Stoner-Wohlfarth model is a traditional and efficient tool to calculate magnetization curves and it can provides further insights on the fundamental physics associated to the magnetic properties and magnetization dynamics. Here, we perform a theoretical and experimental investigation of the quasi-static magnetic properties of anisotropic systems. We consider a theoretical approach which corresponds to a modified version of the Stoner-Wohlfarth model to describe anisotropic systems and a distribution function to express the magnetic anistropy dispersion. We propose a procedure to calculate the magnetic properties for the anisotropic case of the SW model from experimental results of the quadrature of magnetization curves, thus quantifying the magnetic anisotropy dispersion. To test the robustness of the approach, we apply the theoretical model to describe the quasi-static magnetic properties of amorphous FeCuNbSiB ferromagnetic films. We perform calculations and directly compare theoretical results with longitudinal and transverse magnetization curves measured for the films. Thus, our results provide experimental evidence to confirm the validity of the theoretical approach to describe the magnetic properties of anisotropic amorphous ferromagnetic films, revealed by the excellent agreement between numerical calculation and experimental results.

“…6,8 Since the discovery of the effect, MI has been studied in a wide variety of systems, e. g., sheets, 9 wires, [10][11][12][13][14][15][16][17][18] ribbons, [19][20][21][22][23][24] and thin films. [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] In the particular case of films, an increasing interest has been devoted to the effect in single layered, 25,26 multilayered, [27][28][29][30][31][32] and structured multilayered thin films, 30,31,[33][34][35][36][37][38][39] since ...…”

Section: Introductionmentioning

confidence: 99%

Magnetization dynamics in nanostructures with weak/strong anisotropy

Andrade

Corrêa

Viegas

et al. 2014

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We investigate the high-frequency response of magnetization dynamics through magnetoimpedance (MI) effect in Permalloy-based multilayered thin films produced with two different non-magnetic metallic spacers: Cu and Ag. Due to the nature of the spacer materials, we are able to play with magnetic properties and to study both systems with weak/strong magnetic anisotropy. We verify very rich features in the magnetoimpedance behavior and high magnetoimpedance ratios, with values above 200%. We compare the MI results obtained in multilayered thin films with distinct spacers and number of bilayers, and discuss them in terms of the different mechanisms that govern the MI changes observed at distinct frequency ranges, intensity of the magnetic anisotropy, alignment between dc magnetic field and anisotropy direction. Besides, by considering a theoretical approach that takes into account two single models together and calculate the transverse magnetic permeability and the MI effect, we support our interpretation via numerical calculations modeling the effect of weak/strong magnetic anisotropy on the MI response. Thus, we confirm that these features are very important for the use of multilayered films in sensor applications and, both the frequency and field response can be tailored to fulfill the requirements of a given device.