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• CoFeB/(Ag, Pt) multilayer grown onto amorphous substrate. • Role of the damping in the magnetization dynamics. • Role of the magnetic anisotropy in the magnetization dynamics. • Magnetoimpedance in CoFeB/(Ag,Pt) multilayer. We investigate the magnetization dynamics in CoFeB/(Ag, Pt) multilayer films grown onto amorphous substrate engineered to have in-plane magnetic anisotropy and distinct effective damping parameter. We go beyond quasi-static magnetic properties and characterize the dynamic magnetic response by employing ferromagnetic resonance and magnetoimpedance measurements. The link between magnetic features and dynamic magnetic behavior allows us to identify the role of the effective damping parameter and of the magnetic anisotropy on the magnetoimpedance effect in multilayer films. In addition, we consider a theoretical approach to interpret the experimental data and also predict the magnetization dynamics in wider ranges of the explored parameters. From our results, we provide insights to tune the damping parameter and magnetic anisotropy in engineered multilayer films grown onto amorphous substrates. [ABSTRACT FROM AUTHOR]

We investigate the structural and magnetic properties, and the magnetization dynamics in Ni 81 Fe 19 /Pt multilayer systems grown onto rigid and flexible substrates. The structural characterization shows evidence of a superlattice behavior, while the quasi-static magnetization characterization reveal a weak magnetic anisotropy induced in the multilayers. The magnetization dynamics is investigated through the magnetoimpedance effect. We employ a theoretical approach to describe the experimental magnetoimpedance effect and verify the influence of the effective damping parameter on the magnetization dynamics. Experimental data and theoretical results are in agreement and suggest that the multilayers present high effective damping parameter. Moreover, our experiments raise an interesting issue on the possibility of achieving considerable MI% values, even for systems with weak magnetic anisotropy and high damping parameter grown onto flexible substrates. [ABSTRACT FROM AUTHOR]

Abstract: The amorphous alloy Fe90Zr7B3 containing alpha-iron nanocrystallites (known commercially as NANOPERM®) is produced in ribbons by melt spinning and presents magnetic properties that allow its wide applicability in magnetic shielding, low loss RF transformers, choke coils, magnetic sensors and flux-gate magnetometers. In this work, we present a study of the effect of the annealing process realized at different temperatures on the magnetic properties of this material. Comparisons of experimental results of ferromagnetic resonance (FMR) and magnetization measurements show that the precipitation of alpha-iron phase causes the reduction of the coercive field and the in-plane magnetic anisotropy by about 70% in ribbons annealed for 1h at temperatures between 250 and 350°C. [Copyright &y& Elsevier]

We investigate magnetization damping in symmetric NiFe/Ru/NiFe synthetic antiferromagnet using broadband ferromagnetic resonance. The field and frequency linewidth for both, acoustic and optical modes, were measured all along the dispersion relation. These results were compared with a model based on the Landau Lifshitz Gilbert equation. We show that this model explains most of the features observed in the field linewidth measurements, however the phenomenological inhomogeneous linewidth is necessary to fully explain the results. The measured damping parameter for the acoustic mode is in agreement with the intrinsic damping for NiFe, while for the optical mode and enhanced Gilbert damping due to the spin pumping effects was obtained. • Damping of a symmetric synthetic antiferromagnet for optical and acoustic modes. • Precise broadband FMR and linewidth measurements in saturated and spin flop states. • A Landau Lifshitz Gilbert model fits well with the experimental linewidth data. • An enhanced Gilbert damping was obtained for the optical mode. • Phenomenological inhomogeneous linewidth is necessary to explain the results. [ABSTRACT FROM AUTHOR]

Abstract: Using time resolved magneto-optic Kerr effect magnetometry, the precessional reversal properties of continuous soft magnetic layers such as Permalloy and Finemet have been studied in the presence of a weak bias field applied parallel to the initial magnetisation direction. This configuration induces for appropriate pulse width and pulse height, a reversed domain with two domain walls. It will be shown how these time resolved studies can be used to investigate the wall velocity and wall mobility of in-plane magnetised thin films. [Copyright &y& Elsevier]

• Exchange bias in Heusler alloys materials. • Broadband ferromagnetic resonance spectrum of Co 2 FeAl/IrMn multilayers. • Magnetization dynamics at high frequencies. • Effect of IrMn thickness on the dynamical properties of Co 2 FeAl films. • Low damping and small inhomogeneous linewidth broadening. We report an experimental investigation of the quasi-static and dynamic magnetic properties of exchange-biased Co 2 FeAl/IrMn nanostructures. Specifically, we explore the exchange bias effect and the broadband ferromagnetic resonance spectrum of Co 2 FeAl/IrMn multilayers and verify their dependency with the thickness of the antiferromagnet. We observe an evolution of the dynamic magnetic response when samples are compared, and show it is experimentally tunable by varying the IrMn thickness and the angle between the external and bias fields. Our results thus provide further insights on the effect of antiferromagnetic thickness on the dynamical properties of Co 2 FeAl films. Additionally, they place exchange-biased Co 2 FeAl/IrMn nanostructures as interesting systems for applications based on the magnetization dynamics at high frequencies. [ABSTRACT FROM AUTHOR]

Abstract: The magnetostriction in non-oriented electrical steels FeSi3.2% E110 grade samples produced by ACESITA as a function of the magnetic induction for several angles between the applied field and the rolling direction is investigated. The results are discussed in terms of the domain wall motion, magnetization rotation, nucleation and annihilation of domains and evolution of the complex magnetic domain structure present in these steels. [Copyright &y& Elsevier]

Abstract: High-frequency differential magnetic permeability and magnetoimpedance measurements were performed in Fe73.5Cu1Nb3Si13.5B9 as-made and annealed thin films at frequencies up to 1.8GHz. The results show complex dynamical properties characterized by multiple ferromagnetic resonance modes at relatively low frequencies for the amorphous as-made sample. After the thermal treatments, the resonance frequencies increase drastically exceeding the upper limit of 1.8GHz for our equipment. This increase can possibly associated to higher local magnetic fields that are, in turn, associated to the formation of nanocrystalline grains randomly oriented. [Copyright &y& Elsevier]

Abstract: The effect of applied stress on the magnetization process of magnetostrictive Fe78B13Si9 and amorphous Fe73.5Cu1Nb3Si13.5B9 is investigated by calculating the entropy by means of the zipping method to the Barkhausen noise time series. The relative entropy is estimated as the size of the packed time series and is obtained by applying the LZ77 algorithm. Above a given stress level, an increase in the relative entropy is observed, possibly as a result of the decrease in the domain wall width. The results are compared with domain structure observations by Kerr microscopy and to magnetization curves obtained by the inductive method. [Copyright &y& Elsevier]