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Presents a study on the magneto-impedance effect in permalloy/silver (Ag) multilayers with different Ag thickness and number of bilayers. Experimental procedure; Results and discussion; Summary.

Reports on the results of the magnetoimpedance (MI) effect in sharply textured (110)[001]FeSi3%. Permeability and magnetocrystalline anisotropy; Measurements for circular and rectangular samples at different angles.

The dynamic matrix method addresses the Landau–Lifshitz–Gilbert (LLG) equation in the frequency domain by transforming it into an eigenproblem. Subsequent numerical solutions are derived from the eigenvalues and eigenvectors of the dynamic matrix. In this work we explore discretization methods needed to obtain a matrix representation of the dynamic operator, a fundamental counterpart of the dynamic matrix. Our approach opens a new set of linear algebra tools for the dynamic matrix method and expose the approximations and limitations intrinsic to it. Moreover, our discretization algorithms can be applied to various discretization schemes, extending beyond micromagnetism problems. We present some application examples, including a technique to obtain the dynamic matrix directly from the magnetic free energy function of an ensemble of macrospins, and an algorithmic method to calculate numerical micromagnetic kernels, including plane wave kernels. We also show how to exploit symmetries and reduce the numerical size of micromagnetic dynamic-matrix problems by a change of basis. This procedure significantly reduces the size of the dynamic matrix by several orders of magnitude while maintaining high numerical precision. Additionally, we calculate analytical approximations for the dispersion relations in magnonic crystals. This work contributes to the understanding of the current magnetization dynamics methods, and could help the development and formulations of novel analytical and numerical methods for solving the LLG equation within the frequency domain. • New framework for magnetization dynamics using novel dynamic-matrix methods. • Improved methods and analysis for magnetization dynamics around the equilibrium. • Effective reduction of numerical problems by exploiting discrete symmetries. [ABSTRACT FROM AUTHOR]

Observes magneto-impedance effects in amorphous Fe[sub 73.5]Cu[sub 1]Nb[sub 3]Si[sub 13.5]B[sub 9] thin films. Achievement of large magneto-impedance values in field-annealed samples; Observation of transverse magneto-impedance effects with magnitudes comparable to longitudinal case; Elaboration of the results in terms of appropriate magnetic permeability.

Examines the role of magnetic anisotropy in the magnetoimpedance effect in amorphous ferromagnets. Presence of transverse magnetic anisotropy in the field-annealed samples; Effect of transverse annealing on magnetoimpedance spectra; Saturation of magnetoimpedance and magnetization of the sample.

We investigated the microstructural and magnetic properties of nanocrystalline FeCuNbSiB thin films produced through magnetron sputtering followed by heat treatment. Our research focused on film thicknesses (80 nm and 160 nm) and heat treatment temperatures (490 ° C –520 ° C) that resulted in samples characterized by low coercivity and high effective magnetization. Conducting a comprehensive microstructural examination, we employed X-ray diffraction and transmission electron microscopy techniques, including selected area electron diffraction, high-resolution imaging and Fourier transform analysis. Magnetic properties were investigated using an alternating gradient field magnetometer and broadband ferromagnetic resonance. Structural analysis revealed, for all our heat-treated films, a well-defined microstructure characterized by nanograins, with a Fe 3 Si ferromagnetic phase, embedded within an amorphous matrix. Our films exhibit sub-Oe coercivity, reaching as low as 0.51 Oe, along with an increase in effective magnetization from 1170 emu/ cm 3 for the amorphous phase to a maximum of 1260 emu/ cm 3 in the nanocrystalline phase. • FeCuNbSiB thin films were produced through magnetron sputtering, then heat treated. • The Fe 3 Si phase was obtained with crystallite sizes ranging from 11 nm to 15 nm. • Crystallization resulted in sub-Oe coercivity and increased effective magnetization. • Magnetic properties were investigated using AGFM and broadband-FMR techniques. [ABSTRACT FROM AUTHOR]

• 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]

Highlights • Magnetoimpedance in systems with magnetic insulators. • Ferrimagnetic insulator yttrium iron garnet capped by copper. • Magnetoinductive effect in the whole frequency range. • Ferromagnetic resonance effect even at low frequencies. Abstract We investigate the magnetization dynamics through magnetoimpedance effect in films of ferrimagnetic insulator yttrium iron garnet capped by copper. Thereby, we explore the magnetoimpedance in systems with magnetic insulators by varying the thickness of the magnetic material, and probe current frequency. We observe that the difference of electrical nature of the layers composing the films gives rise to the magnetoinductive effect in the whole frequency range, as well as favors the appearance of the ferromagnetic resonance effect even at low frequencies. We discuss the experimental results in terms of the structural features of the magnetic material, its magnetic properties, and the different mechanisms governing the magnetization dynamics. The results place the films of ferrimagnetic insulator yttrium iron garnet capped by copper exhibiting magnetoimpedance effect as very attractive candidates for application as probe element in magnetic sensors operating at low frequencies and with energy-efficient technologies. Further, we disclose an auspicious technique to look at the magnetization dynamics in magnetic materials and we provide a new perspective to solve questions related to the integration of insulator ferrimagnetic materials with the coplanar waveguide in broadband frequency applications. [ABSTRACT FROM AUTHOR]

Highlights • Second order cubic anisotropy presented stronger than the first order in YIG (1 0 0). • The surface anisotropy constants exhibited different behaviors with film thickness. • Second order surface anisotropy becomes relevant even for bulk YIG thickness. • The out-of-plane resonance field angular dependency was explained by the second order surface anisotropy. Abstract In this work, we produced Y 3 Fe 5 O 12 textured films, with thicknesses between 50 nm and 500 nm, onto (1 0 0) Gd 3 Ga 5 O 12 by magnetron sputtering and post annealing, and investigated the first and second order surface and cubic anisotropy constants using the ferromagnetic resonance technique. The surface anisotropy constants exhibited different behaviors with film thickness, with the first order presenting the usual inverse of ferromagnetic layer thickness. Besides this inverse of thickness behavior, the second order also came up with a constant value. In the frame of spin reorientation transition phenomenon, we evaluated volume and surface contribution to the surface anisotropy. Although the second order cubic anisotropy constant is one order of magnitude stronger than the first order, they did not show any explicit thickness dependence. The second order terms of surface and cubic anisotropy appeared to be essential to allow simultaneous fit of in-plane and out-of-plane angular dependence of resonance field. Moreover, they had to be negative to describe the out-of-plane results correctly. Our results raised critical issues that shall be taken into account when explaining the new and recent spintronics and caloritronics effects in YIG. [ABSTRACT FROM AUTHOR]

We study the magnetic properties and broadband microwave absorption of electroplated NiFeCu/Cu multilayered thin films deposited directly on Si (100) substrates. We produced samples with 20 nm thick NiFeCu layers and Cu layer thickness t Cu in the range 0–2.8 nm. Structural properties were studied by grazing incidence X-ray diffraction (GIXRD), while the composition and morphological aspects were studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). GIXRD confirmed the cubic face centered FCC phase of NiFeCu with all diffraction peaks drifting toward lower angles with t Cu . SEM images show the appearance of Cu islands instead of continuous Cu layers. A minimum coercive field of 1.4 Oe is obtained for t Cu = 1.0 nm , while the ferromagnetic resonance linewidth exhibited 200 Oe constant values for t Cu between 0.7 and 2.1 nm. The effective magnetization increases with t Cu , possibly associated to the increase on Fe content as observed by EDX. The effective dynamic anisotropy behavior with t Cu seems to be associated to the island structure observed in the films. [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]

We investigate the asymmetric magnetoimpedance effect in exchange biased NiFe/IrMn multilayers and explore the possibility of tailoring the linear region of the curves around zero magnetic field by playing with the thickness of the ferromagnetic layers, probe current frequency, and the orientation between external magnetic field and exchange bias field direction. We quantify the sensitivity by calculating the | dZ / dH | H = 0 in a wide range of frequencies. The highest sensitivity is observed for the thicker multilayer, reaching ∼ 160 m Ω / Oe at ∼2.0 GHz. The results place exchange biased magnetoimpedance multilayers as attractive candidates for the development of auto-biased linear magnetic field sensors. [ABSTRACT FROM AUTHOR]

We perform a systematic investigation of the static and dynamic magnetic properties of exchange-biased Co 2 FeAl/IrMn films. We analyze the evolution of the coercive field, exchange bias field, rotatable anisotropy and magnetic damping, using broadband ferromagnetic resonance, as a function of IrMn antiferromagnet film thickness. We observe an increase of exchange bias and rotatable anisotropy with the thickness of the IrMn layer. These anisotropies reach nearly constant values for thickness above 20 nm of IrMn, and surprisingly the rotatable anisotropy does not decrease as observed in other systems. We obtain magnetic damping parameters α between 5. 47 × 1 0 − 3 and 8. 89 × 1 0 − 3 , for the CoFeAl/IrMn systems, with no clear correlation with the thickness of the IrMn or the rotatable anisotropy. The present study brings interesting new results on the dynamic properties of magnetic Co 2 FeAl/IrMn systems, and open new challenges for theoretical explanation of the observed effects. • We study Heusler alloy based exchange biased bilayers CoFeAl/IrMn. • We obtain A2 and FCC type crystal structures for CoFeAl and IrMn, respectively. • The exchange bias and rotatable anisotropy increases with the thickness of the IrMn. • The rotatable anisotropy does not decrease for samples with thicker IrMn layers. • No significant correlation on magnetic damping with the rotatable anisotropy. [ABSTRACT FROM AUTHOR]

We study spin rectification effects in NiFe/Ru/NiFe synthetic antiferromagnets at the saturated, non-collinear and antiparallel magnetic states. The change in magnetization orientation at these states allows us to study the angle dependence of spin rectification phenomena by only changing the applied field. This approach avoids the need of changing the sample orientation within the experiment for this kind of studies. Our results show large planar Hall effect contributions to the measured spin rectified voltage with interesting features in the non-collinear and antiparallel states, which bring new possibilities for device design and applications. The results improve the understanding of electrically detected ferromagnetic resonance signals, not only for synthetic antiferromagnets, but also for other samples where the signals coming from the anisotropic magneto resistance effect and the inverse spin hall effect are superimposed. • Spin rectification effects in NiFe/Ru/NiFe synthetic antiferromagnets are studied. • Saturated, non-collinear and antiparallel magnetic states are investigated. • The angle dependence of spin rectification is controlled by the applied field. • Spin rectified signal is dominated by the planar Hall effect. • A sign inversion of the rectified voltage with frequency is observed. [ABSTRACT FROM AUTHOR]

Highlights: [•] Preparation of Ni–Mn–In Heusler alloys by melt spinning technique in ribbon shape. [•] Short annealing effects on the crystal structure, microstructure and magnetic properties. [•] Influence of annealing on the martensitic transformation. [•] Enhancement of the exchange bias effect. [ABSTRACT FROM AUTHOR]

We investigate the broadband ferromagnetic resonance dispersion relation of NiFe/IrMn multilayers using the vector network analyzer ferromagnetic resonance (VNA-FMR) method. Multilayered films with structure [NiFe(20nm)/IrMn (t IrMn)/Ta(3nm)]×10 (with t IrMn=4 and 15nm) were produced onto Si(100) substrates using magnetron sputtering. The dispersion relations of the samples were extracted from the resonance spectra in the range of 0.1–7GHz under magnetic fields of up to±300Oe. Static magnetization curves were also obtained in the same field range. The experimental data were compared with numerical calculations performed using the granular exchange-bias model which takes into account both, the unidirectional and rotatable anisotropy present in the samples. A good agreement between numerical and experimental results was achieved without the need of any frequency or field-dependent parameter. [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: Magnetostriction and Barkhausen noise are investigated in non-oriented electrical steels, with composition FeSi3.2%, corresponding to the E110 grade produced by ACESITA (Brazil), as a function of both, the magnetic induction level and the angle between the applied magnetic field and the rolling direction. The aim of this study is to understand the magnetization and hysteresis loss processes for this steel, identifying the magnetization mechanism taking place when magnetic field is applied in directions not aligned with the rolling direction, mainly at high magnetic induction levels (above 0.8T). It is shown that the Barkhausen noise is always present at these high induction levels which can be associated to domain wall motion and to the nucleation and annihilation of 180° and 90° domains as well as to their evolution with the applied field. Thus, it is shown that the origin of the high induction loss in these samples is the motion of domain walls, irrespective to the angle with respect to the rolling direction. [Copyright &y& Elsevier]

Abstract: The degree of micromagnetic disorder in magnetic amorphous materials is investigated by applying the packing method to the time series obtained, both from Barkhausen noise experiments and simulations of domain wall motion. The observed dependences of the estimated entropy on the applied stress, in the case of experimentally obtained time series, and the width of the Gaussian noise used in simulations, are explained in terms of two regimes of the effect of an external stress applied. [Copyright &y& Elsevier]

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]

• We obtain low damping and small inhomogeneous linewidth broadening in as deposited Co 2 FeAl films. • We observe the emergence of rotatable anisotropy with increasing film thickness. • We quantify the out-of-plane surface anisotropy constant for Co 2 FeAl /Ti interfaces. • We observe low damping and small inhomogeneous linewidth broadening even for thickest 200 nm Co 2 FeAl film. In this work we investigate structural, static and dynamics magnetic properties of Co 2 FeAl (CFA) films, deposited on Si (1 0 0) with Ti buffer and capping layers. We study the evolution of the coercive field, anisotropies, damping constant and linewidth broadening as a function of CFA film thickness in the range 5 nm to 200 nm. We obtain coercive fields weakly dependent on thickness, with values in the range 4.2 Oe to 7.8 Oe. All samples show roughly constant in-plane magnetic anisotropy, and out-plane anisotropy originated from the CFA/Ti interfaces. With increasing thickness we observe the emergence of rotatable anisotropy. We found magnetic damping parameters α between 2.56 × 10 - 3 and 3.45 × 10 - 3 , and inhomogeneous linewidth Δ H o under 10.3 Oe for the whole range of CFA film thickness. These Δ H 0 results are small when compared to the values reported for CFA in literature, specially for films with thickness above 100 nm. The present study contributes to a better understanding of the dynamic properties of magnetic CFA films, and open new potential applications in magneto-impedance sensors, RF shielding and others. [ABSTRACT FROM AUTHOR]

• Isolating magnetic damping mechanisms in a single sample of YIG(001). • Two-magnons magnetic damping extracted without thickness variation. • Surface defects of YIG(001) contribution to the FMR linewidth angular dependence. • Evidence of different surface defects directions on YIG(001). In this work we used the ferromagnetic resonance (FMR) technique to measure the contributions for the magnetic relaxation in Y 3 Fe 5 O 12 textured films deposited onto (001) Gd 3 Ga 5 O 12 by magnetron sputtering. Through the numerical fitting of the angular dependence of the in-plane FMR linewidth measurements we identified the contribution of the Gilbert, two-magnon and mosaicity relaxation mechanisms. Regarding to the line broadening due to two-magnon mechanism, we interpreted it as a result of rectangular defects distributed over the film plane. The overall defects were decomposed into three crystallography direction chosen according to the in-plane FMR resonance field experimental results. We observed the two-magnon scattering rate being relevant for YIG thickness below 150 nm. Although it is also present for thicker samples, the Gilbert mechanism dominates with mosaicity being very important to corroborate the shape of the angular dependence, but with small amplitude. We point out the relevance of our finding regarding two-magnon scattering effect in YIG thin films, directly impacting in an overestimation of the spin pumping contribution to the FMR line broadening in YIG/ heavy-metal systems. [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: This work presents the dynamic and static magnetic properties of an 85nm-thick amorphous thin film precursor of the well-known Finemet material, deposited by RF sputtering. Hysteresis evidences in-plane isotropic properties that are distinguished as contributions of hard and soft axis simultaneously. High-frequency permeability measurements were performed by using the network inductive method in the frequency range 100kHz–1.8GHz. The low-field FMR relation dispersion obtained from the permeability spectra shows peculiar properties, from which the effects of stress-induced anisotropy are discussed. [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: Very high magnetoimpedance (MI) measured at frequencies up to 1.8GHz in single and multilayered thin films with composition Fe73.5Cu1Nb3Si13.5B9 and (Fe73.5Cu1Nb3Si13.5B9+Cu) are reported. The magnetic properties of both systems are also compared. MI ratio as high as 300% for the multilayered samples were obtained. [Copyright &y& Elsevier]

Abstract: The statistical properties of the Barkhausen noise (BN) in thin amorphous films are studied as a function of both the nominal composition and the thickness. BN was observed in single films with nominal compositions Fe73.5Cu1Nb3Si22.5− x B x (with and 9) in the thickness range 20nm–5μm. The distributions of Barkhausen jump sizes and duration times were obtained and fitted to power laws with critical exponents and , respectively. [Copyright &y& Elsevier]

Abstract: In this work, we report a comparative study of the magnetoimpedance in sandwiched films with the structure FS/Cu/FS (SWS) and FM/Cu/FM (SWM) where FS=single-layer FeCuNbSiB and FM=multilayer FeCuNbSiB/Cu. Magnetoimpedance ratios of 250% were obtained for the real part of the impedance in the SWM sample, while variations of 100% were reached for the SWS sample. [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]

In this work, we studied soft magnetic CoP alloys prepared through electrodeposition on Si substrates with a NiCu buffer layer. AFM and AGFM measurements showed compact and granular layers with a coercive field of 10 Oe for thicknesses higher than 1500 nm. A magnetoimpedance effect of about 5% was observed for a measuring frequency of 1.8 GHz. [Copyright &y& Elsevier]

Abstract: We study the magnetic properties at high frequency of new structures of the tri-layer samples. The magnetoimpedance effect was analyzed in FM/i/Cu/i/FM sandwiched layers, where the ferromagnetic layer (FM) is, in fact, a multilayered film [F (10nm)+Cu (1nm)]×50 and F is the amorphous ferromagnetic alloy Fe73.5Cu1Nb3Si13.5B9 and i is an isolating layer produced by magnetron sputtering. The effect of, both, the probe current frequency (in the range 10MHz–1.8GHz) and the dimensions of the magnetic and non-magnetic layers of the MI response were investigated. A comparison between samples with and without the isolating layer is discussed. MI ratios of 220% were obtained for samples at 180MHz with a ferromagnetic and Cu width layers of 2 and 1mm, respectively. [Copyright &y& Elsevier]