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The growth of nanostructured materials by means of different deposition methods employing nanoporous anodic aluminum oxide membranes as patterned templates has been widely used during last years due to the outstanding features displayed by these nanoporous templates. Here we report on the synthesis, morphology and magnetic properties exhibited by novel magnetic 1D and 2D nanostructured materials having nanowire or antidot thin films geometry, respectively, together to that of geometrically diameter modulated ferromagnetic nanowires. Their magnetic properties will be analyzed and discussed based on the different anisotropic behavior derived from their morphological and microstructural features. [ABSTRACT FROM AUTHOR]

Cobalt nanowire arrays spatially distributed in 2D and 3D arrangements have been performed by pulsed electrodeposition into the pores of planar and cylindrical nanoporous anodic alumina membranes, respectively. Morphological characterization points out the good filling factor reached by electroplated Co nanowires in both kinds of alumina membranes exhibiting hexagonally self-ordered porous structures. Co nanowires grown in both kinds of alumina templates exhibit the same crystalline phases. DC magnetometry and First Order Reversal Curve (FORC) analysis were carried out in order to determine the overall magnetic behavior for both nanowire array geometries. It is found that when the Co nanowires of two kinds of arrays are perpendicularly magnetized, both hysteresis loops are identical, suggesting that neither the intrinsic magnetic behavior of the nanowires nor the collective one depend on the arrays geometry. FORC analysis performed along the radial direction of the Co nanowire arrays embedded in the cylindrical alumina template reveals that the contribution of each nanowire to the magnetization reversal process involves its specific orientation with respect to the applied field direction. Furthermore, the comparison between the magnetic properties for both kinds of Co nanowire arrays allows discussing about the effect of the cylindrical geometry of the template on the magnetostatic interaction among nanowires. [ABSTRACT FROM AUTHOR]

Abstract: In this work, we highlight our recent progress in the synthesis and characterization of functional nanomaterials based on Fe–Pd ferromagnetic alloys by means of template-assisted deposition techniques employing highly ordered nanoporous alumina membranes, such as ordered arrays of nanowires and antidots thin films. Special attention is paid on their basic magnetic properties, such as coercivity, remanence and magnetic anisotropy, and their dependence on the microstructure and morphological parameters of the ordered arrays. [Copyright &y& Elsevier]

Abstract: Magnetic entropy change and refrigerant capacity for an applied magnetic field variation of 1.5T have been determined in the temperature range of 293–700K for the as-quenched polycrystalline Fe73.2Pd26.8 melt-spun ribbons alloy. Samples show a major magnetic phase with the fct crystal structure and a Curie temperature of 553K, at which a second order magnetic phase transition occurs. A maximum magnetic entropy change of 1.04Jkg−1 K−1 was achieved at 550K, while the maximum refrigerant capacity of 108J/kg is attained at the applied field of 1.5T. The field dependence of the magnetic entropy change for this material follows the phenomenological universal curve and at the temperature of the peak corresponds to a large field independent exponent of n =0.84. Extrapolated value of field depending RC Area at 5T reach above 300J/kg, which is comparable to that of some of the best-known Fe-doped GdSiGe coolant compounds. [Copyright &y& Elsevier]

Abstract: We report about the ambient conditions and electrolytes influence on the synthesis of self-organized titania nanotube arrays prepared by anodic oxidation. Arrays of randomly disordered Titanium dioxide nanotubes with pores diameter ranging between 60 and 100nm, wall thickness of 25 up to 40nm and around 300nm nanotubes length, can be prepared under HF electrolyte and its mixtures with sulphuric acid at RT anodization. [Copyright &y& Elsevier]

Abstract: We report on the temperature evolution of the magnetic behavior of Ni-riched microwires obtained by the well-known Taylor–Ulitovsky method, with nominal compositions of Ni80Si6B14 and Ni78Si8B14, respectively. We study the Differential Scanning Calorimetry curves in the temperature range between RT to 600°C, and the thermomagnetic evolution up to 800°C at the two applied magnetic field values of 0.1 and 0.5T for both, glass-coated microwires and uncovered microwires with the coating removed by selective etching in HF solution. We also correlate our measurements with magnetic domain pattern obtained by means of Bitter technique and RT VSM axial hysteresis loops. The evolutions of the magnetic and hysteresis properties for the as-quenched and annealed microwires are compared as a function of their thermo-magnetic history. [Copyright &y& Elsevier]

Abstract: We present a study by intermittent contact atomic force microscopy technique, using the corresponding line profile analysis, performed in as-cast amorphous and Joule heated nanocrystalline Fe91Zr7B2 ribbons. The average grain size of the nanocrystalline phases estimated from AFM images, (≈10–15nm), correlates well with respect to that obtained from neutron powder diffraction. The differences in the relative amount of amorphous to nanocrystalline phases estimated from both techniques, suggest that the onset of the crystallisation process begins at the ribbon surface. [Copyright &y& Elsevier]

A very high giant magnetoimpedance (GMI) up to 420% and sensitivities up to 60%/Oe have been achieved in commercial Vitrovac® 6025 Co67Fe4Mo1.5Si16.5B11 amorphous ribbons. A relatively low frequency range of 0.5–10 MHz and driving current intensities between 1.5 and 15 mA in combination with high sensitivities, low GMI hysteresis with respect to external magnetic field make this material very attractive for low field sensing processes. Special treatments under load without heating result in additional stability and favorable noise to signal ratio. We explain these outstanding GMI properties taking into account extra uniform magnetization processes and longitudinal magnetic anisotropy. The complex study of the magnetic and GMI properties shows, that equilibrium of various parameters of GMI medium is an additional guarantee of stable functionality. [Copyright &y& Elsevier]

The magnetoimpedance response shown by amorphous and nanostructured ultrasoft magnetic materials is a very promising effect suitable for application in a great variety of fields, as magnetic stress, strain or torsion sensors. However, magnetoimpedance hysteresis, which is related to irreversibilities in transverse magnetization processes, is an undesired effect for technological devices. Various thermal treatments were performed on Co-rich amorphous alloys to obtain quasi-reversible magnetoimpedance. Stress-relief-like treatments were found to reduce in a very significant way the hysteretic behaviour. Moreover, this improvement was analysed at the relaxation frequencies of the samples, where the magnetoimpedance has its maximum value. An attempt to understand the origin of this hysteresis reduction is given in this paper. The proposed explanation is based on the improvement of the reversibility in the magnetization processes, as a consequence of the decrease in the anelastic component of the induced anisotropy and the removal of wall pinning centres. [ABSTRACT FROM AUTHOR]

Abstract: Fe–30%Pd alloys in ribbon and nanowire geometry have been prepared. Ribbon samples were produced by the melt-spinning technique in the Ar environment. FePd nanowires, having about 35nm in diameter, 105nm inter-nanowires distance and around 4μm in length, were synthesized into nanoporous anodic alumina membranes as templates. Energy dispersive X-ray microanalysis of ribbons shows an average atomic composition of Fe (73.2%) and Pd (26.8%). The X-ray diffraction at RT analysis was performed on both surfaces, free and wheel side, of the melt-spun ribbon. It shows the coexistence of two phases: fct and bct FePd, but with differences between both surfaces consisting the existence of Fe oxides (Fe2O3 and Fe3O4) and a textured 200 reflection in the free side. Heating and cooling thermomagnetic curves exhibit a reversible behaviour from RT to 720K, but around 770K a clear irreversible transformation takes place. [Copyright &y& Elsevier]

Amorphous ferromagnetic wire with a highly positive saturation magnetostriction coefficient, made of Fe73.5Si13.5B9Nb3Cu1, was simultaneously submitted to both, an AC current passing through it and a torsional stress, in order to induce a helical magnetic anisotropy in the wire that modifies its domain structure and therefore the magnetic response of the sample. The aim of this work is to study the reactive, resistive and impedance behaviour in this Fe-rich wire, submitted to different applied torsional stresses, and for several values of the AC current amplitude through the wire (5–20 mArms), in the low frequency range, f. The experimental results are explained on the basis of the core-shell model. [Copyright &y& Elsevier]

Large scale production of single crystalline phase of Heusler Co 2 FeSi alloy microwire is reported. The long microwire (∼1 km) with the metallic nucleus diameter of about 2 µm is characterized by well oriented monocrystalline structure ( B2 phase, with the lattice parameter a  = 5.615 Å). Moreover, the crystallographic direction [1 0 1] is parallel to the wire’s axis along the entire length. Additionally, the wire is characterized by exhibiting a high Curie temperature ( Tc  > 800 K) and well-defined magnetic anisotropy mainly governed by shape. Electrical resistivity measurement reveals the exponential suppression of the electron-magnon scattering which provides strong evidence on the half-metallic behaviour of this material in the low temperature range. [ABSTRACT FROM AUTHOR]

Abstract: Arrays of Ni nanowires electrodeposited into self-aligned and randomly disordered titania nanotube arrays grown by anodization process are investigated by X-ray diffraction, SEM, rf-GDOES and VSM magnetometry. The titania nanotube outer diameter is about 160nm, wall thickness ranging from 60 to 70nm and 300nm in depth. The so-obtained Ni nanowires reach above 100nm diameter and 240nm length, giving rise to coercive fields of 98 and 200Oe in the perpendicular or parallel to the nanowires axis hysteresis loops, respectively. The formation of magnetic vortex domain states is also discussed. [Copyright &y& Elsevier]

We report on fabrication, structural and magnetic properties of novel Heusler-type glass coated Ni2FeSi microwires that were prepared by the Taylor-Ulitovsky method, having a metallic nucleus diameter about 3.9 μm and total sample diameter of 39 μm. This single step and low cost fabrication technique offers to prepare up to km of glass-coated microwires starting from few g of cheap elements for diverse applications. The X-ray diffraction data from the metallic nucleus indicates L21 crystalline structure (a = 5:563 Å), with a possible DO3 disorder. Magnetic measurements determined the Curie temperature well above the room temperature (770 K) together with uniform easy magnetization axis of the metallic core, which predisposes this material to a suitable candidate for spintronic applications. [ABSTRACT FROM AUTHOR]

Abstract: Circumferential magnetization curves have been derived from the imaginary component of the impedance response in an Fe73.5Si13.5B9Cu1Nb3 amorphous wire. Measurements were performed at 1kHz driving frequency, and 0.05– 20mArms current amplitude range. Axial DC fields from 0 to 100Oe have been simultaneously applied in order to detect the magnetoinductive effect. The circular magnetization curves are compared with quasi-static longitudinal magnetization ones, and the results are analyzed on the basis of the core-shell model for a wire with positive magnetostriction. [Copyright &y& Elsevier]

Abstract: We report on the structural and morphological features of self-aligned titanium oxide nanotube arrays grown by electrochemical anodization in different electrolytes comprising aqueous acidic media or organic neutral media, and at several potentiostatic voltages ranging between 12 and 60V. The results show an improvement in the self-alignment of the nanotube arrays and an increase of about 10,000% in the nanotubes length obtained by anodization performed with NH4F in ethylene glycol electrolyte, respect to the case obtained employing the aqueous electrolytes. [Copyright &y& Elsevier]

The Joule heating is used to obtain different degrees of crystallisation in Fe87Zr6Cu1B6 and Fe91Zr7B2. Neutron diffraction experiments have been performed on a single ribbon to follow the nanocrystallisation under the same conditions. Hysteresis loops show the evolution of the saturation magnetisation and coercive field. The size of the crystallites remains 10–15 nm, which is smaller than in samples nanocrystallised by treatment in furnaces. [Copyright &y& Elsevier]

Correlationship between surface magnetic properties studied using the MOKE technique and giant magnetoimpedance effect (GMI) of nearly-zero magnetostrictive Co 66.5 Fe 3.5 Si 12.0 B 18.0 amorphous ribbons in as-cast state has been investigated in the frequency range of 10 MHz–1.5 GHz. It was found that the surface anisotropy is different in the sides of the ribbon: it is transversal to the ribbon axis with multiple domain walls in one side and axial with a single domain wall in the other. The effect of permanent bias current on surface domain structure was investigated and it was found that the multidomain transversal is very sensitive to the bias current while the axial anisotropy is practically not affected by the applied bias current. This finding can be applied in design of highly sensitive material for magnetic sensors. [ABSTRACT FROM AUTHOR]

Long range hexagonally ordered TiO 2 nanotube arrangements have been synthesized by employing a novel strategy consisted of combining the well-known Laser Interference Lithography technique together with electrochemical anodization methods. By properly tuning the fabrication parameters that make match between both techniques, TiO 2 nanotube arrays having near 32 nm of inner diameter, wall thickness around of 25 nm and 210 nm of lattice parameter were anodically grown on pre-patterned Ti foils over large sample surface areas, typically of several squared centimetres in size. This opens the possibility to the development of new types of functional devices based on self-organized morphologies of anodic TiO 2 nanotubes, requiring both high spatially ordered and defect-free nanotube arrangements. [ABSTRACT FROM AUTHOR]

Thermomagnetic properties and magnetocaloric effect (MCE) in Ni 50.3 Mn 36.5 Sn 13.2 Heusler alloy ribbons are reported. Large magnetocaloric response has been obtained for μ 0 H = 3 T in both the reversible adiabatic change in temperature Δ T ad (−6.3 and +4.7 K) and the isothermal change in the total entropy Δ S T (+11.8 and −2.2 J K −1 kg −1 ), respectively at the temperature T str = 271 K at which the magnetostructural phase transition from the low-temperature Martensite phase (MP) to the high-temperature Austenite phase (AP) takes place, and at T CA = 311 K at which the magnetic phase transition in the AP occurs. The MCE has been studied through the Stoner’s magnetocaloric parameter ξ S (Stoner EC. Phil Mag 19 (1935) 565), and a generalized expression for the equations of state for magnetic materials is presented. The phase coexistence of the MP and AP has been studied via their respective sublattice with opposite-aligned magnetic moments by means of the effective magnetic anisotropy density e A induced by the supercooled (superheated) secondary AP (MP) in the MP (AP). Magnetic fields higher than the critical value of μ 0 H R = 0.5 T produce alignment of the two magnetic moments and hence a change in the magnetic ordering in the MP from antiferromagnetic to ferromagnetic, resulting in a thermomagnetic behavior in which the field-cooling and field-heating magnetizations become coincident, the induced anisotropy vanishes e A = 0 and the metastability disappears. New tentative methods to obtain the spontaneous magnetization of both MP and AP and their respective fractions in the phase coexistence range are reported. [ABSTRACT FROM AUTHOR]

We have studied the effect of Mn doping on structural and magnetic properties of Co2FeSi Heusler alloy. Co2FeSi, Co2Mn0:25Fe0:75Si and Co2Mn0:5Fe0:5Si alloys were prepared by melt spinning technique which offers fast and simple production of large amount of materials in a single production step. The rapid quenching method provides an opportunity to prepare Heusler alloys with highly ordered L21 structure confirmed by X-ray analysis in all the samples. Magnetic measurements revealed high Curie temperatures (> 1000 K) and well defined easy magnetization plane parallel with the ribbon plane. Those attributes predispose given samples for applications in spintronics. [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]

Abstract: An improvement of the magnetocaloric response in Ni50.0Mn35.5In14.5 Heusler alloy ribbons after annealing is reported. Furthermore, the phase of the annealed sample at room temperature can be austenite or martensite depending on the annealing conditions. Short-time thermal treatments during 10min at temperatures of 1048 and 1073K enhance both the maximum values of structural and magnetic entropy changes , and the refrigerant capacity (RC) of the as-spun sample. For a magnetic field value of 3T, an enhancement in of ∼175% and ∼40%, and in RC of ∼25% and ∼20%, have been obtained in the temperature ranges where these structural and magnetic entropy changes take place, respectively. In addition, the values have been calculated using both the Clausius–Clapeyron equation and the Maxwell relation, showing a good agreement between them in the main existing first-order phase transitions. [Copyright &y& Elsevier]

Abstract: Highly ordered Nanoporous Alumina Membranes (NPAMs) with a precise control of the pore size and different porosity but thickness around 63μm were fabricated by the two-step anodization process using different acidic aqueous solutions, oxalic (Al-Ox), sulfuric (Al-Sf), and phosphoric (Al-Ph) acids, respectively. The pore size was controlled by properly changing the anodization voltage and the electrochemical bath conditions, obtaining the following average pores diameter values, dp , as determined by scanning electron micrographic analysis: Al-Ox (dp =46±2nm), Al-Sf (dp =27±2nm), and Al-Ph (dp =240±20nm). A pore increasing of around 5% for samples Al-Ox and Al-Sf was obtained after membranes immersion in 5wt.% phosphoric acid for a certain etching time. Electrochemical characterization of NPAMs was performed with the samples in contact with NaCl solutions at different electrolyte concentrations. Ionic transport numbers and effective membrane fixed charge were determined from membrane potential measurements, which clearly show the significant influence of the pore diameter on ions transport. Moreover, frictional and electrical effects on mass transfer parameters (salt and ions diffusion coefficients) into the pores of alumina membranes were also evaluated from these results. [Copyright &y& Elsevier]

Nanoporous titania (nPTI) has been prepared by electrochemical processes and functionalized by photochemical activation of condensed acrylic acid vapors (AcAc). The nPTI surfaces obtained after electrochemical etching in HF electrolytes at constant potential consisted of nanotube disordered arrays. Elastic recoil detection and Rutherford backscattering spectroscopy studies confirm the presence of an in-depth carbon based layer, previous to the AcAc polymerization. The subsequent AcAc functionalization affected only a few molecular monolayers since the process did not modify the nPTI structure observed by scanning electron microscopy. In fact, X-ray photoelectron spectroscopy confirms the presence of a carboxylic group contribution in the C 1s core-level spectrum only after AcAc polymerization of nPTI. Such results are of relevance for cellular attachment of human mesenchymal stem cells, whose adhesion onto nPTI is drastically enhanced after AcAc biofunctionalization. [ABSTRACT FROM PUBLISHER]

Abstract: The magnetic structure of amorphous and thermal annealed glass coated microwires is studied by thermomagnetic, DSC, and Bitter domain pattern techniques. The long-range dipolar interaction between parallel aligned microwires and the appearance of large Barkhausen jumps steps in the axially magnetized loops are discussed in terms of reversal magnetization process. [Copyright &y& Elsevier]

• Classical FORC investigation of functional nanowires was performed. • Unique TFORC analysis was employed as a trivial characterization technique. • FORC and TFORC analysis showed a presence of shape memory behavior. [Display omitted] Magnetic characterization of ferromagnetic Ni-Fe-Ga shape memory nanowires using a temperature-dependent FORC analysis is shown. The hysteresis loops' shape indicates a magnetic anisotropy that is governed by the magnetostatic interaction among neighboring nanowires. FORC measurement proved that the Ni-Fe-Ga nanowires' array is a multi-domain and highly interacting system. The FORC analysis shows a minimal coercivity distribution that points to a uniform and homogeneous nanowires' array. The change of the vertical spread of the FORC distribution divergence at about 395 K supports the ferromagnetic shape memory behavior and the structural transformation of the presented nanowires. The previous results are also supported by a unique TFORC analysis, showing structural changes within the transformation temperature region. [ABSTRACT FROM AUTHOR]

Abstract: Here we report on the domain wall dynamics in amorphous glass-coated FeCuNbSiB microwires measured in the temperature range from 77 up to 400K. At low temperatures below 200K, the domain wall velocity is proportional to the applied magnetic field. At temperatures above 200K, two regions have been found: one with low domain wall mobility at low fields and another one with high domain wall mobility at high fields. The different regions of the domain wall dynamics are treated in terms of the change of the domain wall configuration from transversal to vortex one. Moreover, non-linear regime is shown at low fields at the temperature 373K as a result of the domain wall interaction with the local defects. [Copyright &y& Elsevier]

In this work, we have studied the magnetic properties and magnetoimpedance behaviour in commercial Vitrovac® 6025 low-magnetostriction ribbons as a function of the frequency and the intensity of the driving current. A very high value of the giant magnetoimpedance effect (GMI) ratio up to 420% and sensitivity of 57%/Oe have been achieved at a relatively low frequency of 3.5 MHz for the current intensity Irms=11 mA. Although the decrease of the alternating current, up to 1.5 mA at a frequency of 3.5 MHz leads to some decay of the GMI ratio up to 300% and sensitivity of 42%/Oe, these values are still very attractive for applications in magnetic field sensors. [Copyright &y& Elsevier]

Abstract: Heusler alloy Ni50.0Mn35.5In14.5 ribbons were prepared by melt-spinning technique. Several short time annealings were carried out in order to enhance the exchange bias effect in this alloy ribbon. The magnetic transition temperature increases with the annealing, compared to the as-spun sample, however no significant differences in respective Curie temperatures were observed for austenite and martensite phases in such annealed samples. Exchange bias effect is observed at low temperatures for all samples and practically vanishes at 60K for the as-spun sample, whereas for the annealed ribbons it vanishes at 100K. [Copyright &y& Elsevier]

Abstract: Both the axial and off-diagonal magnetoimpedance (MI) effect in Fe80B20 amorphous ribbons were measured trough the voltage across the sample and using a pick-up coil wound around it, respectively. Two different ribbons were studied; one in the as-quenched state and other was produced under a transverse magnetic field of 0.07T in the ribbon plane (field quenched). In spite of the small anisotropy induced in the ribbon during this field quenching procedure, the off-diagonal MI allowed us to differentiate both samples. Asymmetric two-peak behavior of the field dependence of the off-diagonal MI was observed, which can be related to the inhomogeneous induced anisotropy in field-quenched samples. [Copyright &y& Elsevier]

Abstract: The skin penetration depth of Fe-rich wires is obtained in this work, from the impedance measurements, as a function of applied magnetic field and torsional stress. The Fe73.5Si13.5B9Nb3Cu1 wires have been submitted to different annealing treatments in order to get the softest magnetic behaviour in the nanocrystalline state. A decrease in electrical resistivity and improvement of the soft magnetic properties of the wire annealed at 565°C is observed. Changes in skin penetration depth of up to 36μm are achieved with a small torsion in the nanocrystallized wire. Results can be understood by the dependence of permeability on applied magnetic field and torsional stresses. [Copyright &y& Elsevier]

Abstract: In this work, we present some results concerning the magnetoimpedance and stress impedance in Fe70Cr10B20 ribbons. A high response is obtained at low values of the applied field and stress, making it possible to develop sensitive devices that could detect small values of magnetic fields and/or tensile stresses. Sensitivities, per unit length, to the applied tensile stress of up to 14%/mMPa are measured under tensile stresses of 40MPa in the case of the annealed sample. [Copyright &y& Elsevier]

An anomalous magnetic behaviour has been observed for transition metal (Fe, Co and Ni) based antidot nanostructures by modifying only the lattice geometry of the nanoholes array. A series of ferromagnetic, FM, antidot arrays have been fabricated by depositing them onto nanoporous alumina membranes with different pore diameters, d, varying in the range between 32 ± 2 and 93 ± 1 nm and maintaining fixed the inter-holes distance, D int = 103 ± 2 nm, and layer thickness, t = 20 nm, but reducing the edge-to-edge separation between adjacent antidots, (W = D int – d). A noticeable change of the in-plane coercivity dependence with W has been observed with an in-plane critical edge to edge distance, W C// , at which the in-plane coercivity behaviour with W is changed. In addition, for antidot samples with large W the in-plane hysteresis loops show single-step magnetic behaviour. Meanwhile, the INP hysteresis loops with W < W C// show multistep magnetic behaviour. The decreasing of the in-plane coercivity for FM-antidot samples with W < W C// is correlated with the increase of the out-of-plane contribution to the magnetic anisotropy i.e. increase the out-of-plane coercivity with increasing the nanohole size of antidots. These findings point towards a new nanotechnological strategy of fabrication arrays of magnetic bits, i.e., basic elements for magneto-optic perpendicular recording patterned media, embedded into a continuous 2D structural system and spintronic devices. [ABSTRACT FROM AUTHOR]

Abstract: The magnetoimpedance (MI) effect (influence of magnetic field), torsion impedance effect (influence of torsional stresses) and a torsion magnetoimpedance (effect produced by torsion in the magnetoimpedance effect) are shown for as-cast wires. The results can be explained by the influence of torsion induced anisotropy in the magnetization processes at the chosen drive current frequency of 1MHz. Resistance and reactance responses of 40% and 48%, respectively are found. [Copyright &y& Elsevier]

Abstract: The influence of isothermal annealing (1h at 600°C in Ar atmosphere) on the soft magnetic properties and magnetoimpedance (MI) effect has been studied in ribbons of the following Nanoperm alloys: Fe91Zr7B2, Fe88Zr8B4, Fe87Zr6B6Cu1 and Fe80Zr10B10. A maximum MI ratio of about 27% was measured for the nanocrystalline alloy Fe87Zr6B6Cu1 at a driving frequency of 0.2MHz. The thermal annealing led to magnetic softening for this alloy, while a hardening is observed for the Fe80Zr10B10 alloy. [Copyright &y& Elsevier]

Abstract: The evolution of the magnetic properties of Fe70Cr10B20 alloy, initially in amorphous state, is studied during the whole crystallization process, from room temperature to 800°C. Neutron thermodiffraction has been used in order to follow all the structural changes that take place in the sample, including the appearance of tetragonal phases and polymorphic transformations. The formation of these tetragonal phases, with high magnetic anisotropy, leads to a degradation of the soft magnetic response. The study of the correlation between structure and magnetic response helps to optimize the composition and heat treatments in these materials for their application in sensor devices. [Copyright &y& Elsevier]