Taylor-Ulitovsky Technique Research Articles

GMR and Kondo Effects in Cu-Co Microwires

We studied the effect of annealing on magneto-transport, magnetic, and structural properties of Cu100−x Co x (x = 5, 10, 20) glass-coated microwires prepared using the Taylor-Ulitovsky technique. Both as-prepared and annealed samples exhibit magnetoresistance effect. We observed a Kondo-like effect in as-prepared and annealed Cu95Co5 microwire and a significant increase of the giant magnetoresistance (GMR) in all studied Co-Cu after annealing. The origin of GMR effect and Kondo-like behavior is discussed considering structural changes of the annealed samples.

Engineering of Magnetic Softness and Magnetoimpedance in Fe-Rich Microwires by Nanocrystallization

We studied the correlation of magnetic properties, structure, and giant magnetoimpedance (GMI) effect in Finemet-type FeCuNbSiB microwires. We observed that the GMI effect and magnetic softness of glass-coated microwires produced by the Taylor–Ulitovsky technique can be tailored by heat treatment. We observed a considerable magnetic softening of studied microwires after annealing. This magnetic softening correlates with the devitrification of amorphous samples. Amorphous Fe-rich microwires exhibited a low GMI effect (GMI ratio below 1%). Considerable enhancement of the GMI effect (GMI ratio up to 125%) has been observed in heat-treated microwires with a nanocrystalline structure.

Magnetoresistance and Kondo-like behaviour in Co5Cu95 microwires

We studied the effect of the annealing on the structure, transport properties and the magnetoresistance of Cu95Co95 glass-coated microwires prepared by Taylor-Ulitovsky technique. We observed a significant enhancement of the magnetoresistance, MR, effect in the samples annealed at 400 °C. On the other hand low temperature annealing (150–200 °C) allowed stress relaxation and elimination of the texture observed in as-prepared samples, although only slightly affects the MR effect. Annealing considerably affects the temperature dependence of resistivity. We observed resistivity minimum in both as-prepared and annealed samples associated with the Kondo effect. This minimum persists even under magnetic field in as-prepared samples. In annealed sample minimum disappears under applied magnetic field. Observed enhancement of the MR effect therefore must be attributed to the structural changes of the studied samples.

Engineering of the GMR Effect in CuCo Microwires with Granular Structure

We prepared Cu100−x Co x (x = 5,10,20) glass-coated microwires by Taylor-Ulitovsky technique and studied the influence of annealing on structure and giant magnetoresistance (GMR) effect. We observed a significant improvement of the GMR effect in the samples annealed at high temperature (400°C) with longer annealing time. On the other hand low temperature annealing (150–200°C) only slightly affects the GMR effect. Considerable enhancement of the GMR effect related to structural changes of the studied samples after annealing is promising for technical applications.

Simultaneous Detection of Giant Magnetoimpedance and Fast Domain Wall Propagation in Co-Based Glass-Coated Microwires

The magnetic properties of as-prepared and annealed amorphous $\text{Co}_{{50}.{69}}{{\text {Fe}}_{{8}.{13}}}{{\text {Ni}}_{{17}.{55}}}{{\text {B}}_{{13}.{29}}}{{\text {Si}}_{{10}.{34}}}$ and glass-coated microwires produced by the Taylor–Ulitovsky technique are investigated systematically. Magnetic-field frequency dependences of magnetoimpedance (MI), domain-wall (DW) velocity, and hysteresis loops were measured. At certain annealing conditions, high MI and fast DW propagation simultaneously coexist. The results suggest criteria for the selection of materials for high-performance magnetic sensors.

Preparation and Characterization of Fe-Pt and Fe-Pt-(B, Si) Microwires

We have prepared Fe-Pt and Fe-Pt-(B, Si) microwires using the Taylor–Ulitovsky technique and studied their magnetic properties. Magnetic properties considerably depend on the metallic core composition. Microwires present either amorphous or a mixture of amorphous and nanocrystalline phases with a presence of face-centered cubic $\text{FePt}_{3}\;(\text{A1})$ disordered phase in the as-prepared state. We obtained microwires with coercivities from 4 to 140 Oe, which can be explained considering different metallic nucleus microstructures.

Grain size refinement in nanocrystalline Hitperm-type glass-coated microwires

We present a new-Fe38.5Co38.5B18Mo4Cu1 Hitperm glass-coated microwires obtained by Taylor-Ulitovsky technique with nanocrystalline structure consisting of about 23nm of BCC α-FeCo and an amorphous precursors in as-prepared samples. Annealing resulted in a considerable decrease of such nano-grains down to (11nm). Obtained results are discussed in terms of the stress diffusion of limited crystalline growth and the chemical composition. Rectangular hysteresis loops have been observed on all annealed samples that are necessary conditions to obtain fast domain wall propagation. An enhancement of the domain wall velocity as well as mobility after annealing has been obtained due to the structural relaxation of such grains with positive magnetostriction. These structure benefits found in the nanocrystalline Hitperm glass-coated microwires are promising for developing optimal magnetic properties.

Effect of annealing on magnetic properties of nanocrystalline Hitperm-type glass-coated microwires

We studied magnetic properties of Fe38.5Co38.5B18Mo4Cu1 Hitperm-like glass-coated microwires obtained by Taylor-Ulitovsky technique with nanocrystalline structure consisting of about 20–30 nm BCC α-FeCo and an amorphous precursor in as-prepared samples. We observed a considerable decrease of the average grain size (from about 23 to 11 nm) after annealing. As-prepared and annealed Fe38.5Co38.5B18Mo4Cu1 Hitperm-like glass-coated microwires present rectangular hysteresis loops and fast domain wall propagation. We measured and analyzed the frequency dependence of the switching field dependence and domain wall dynamics in as-prepared and annealed Hitperm-type microwires. Obtained results are discussed in terms of the microstructural relaxation, grains refinement and internal stresses relaxation. An enhancement of the domain wall velocity as well as mobility after annealing has been attributed to the structural relaxation of such grains with positive magnetostriction.

Optimization of Soft Magnetic Properties in Nanocrystalline Fe-Rich Glass-Coated Microwires

We have studied Hitperm-type and Finemet-type glass-coated microwires with a nanocrystalline structure. In Hitperm-type microwires where the nanocrystalline structure has been obtained directly after melt quenching using the Taylor–Ulitovsky fabrication technique, we observed rectangular hysteresis loops and studied the domain wall propagation. We measured and analyzed the switching field dependence on the frequency in as-prepared and annealed Hitperm-type microwires. A conventional annealing results in a drastic change of the frequency dependence of the switching field. This effect might be interpreted considering the stress relaxation process. We have also studied the correlation of magnetic properties, structure, and giant magnetoimpedance (GMI) effect in Finemet-type FeCuNbSiB microwires prepared by the Taylor–Ulitovsky technique. We observed that both GMI effect and magnetic softness of Finemet-type glass-coated microwires can be tailored by heat treatment, and after annealing a considerable magnetic softening of studied samples has been achieved. This magnetic softening correlates well with the devitrification of amorphous samples. Amorphous Fe-rich microwires exhibit a low GMI effect (GMI ratio below 1%). A considerable enhancement of the GMI effect (GMI ratio up to 100%) has been observed in heat-treated microwires developing a nanocrystalline structure.

Tuning of Magnetic Properties of Ni-Mn-In-Co Heusler-Type Glass-Coated Microwires

We report on magnetic properties and structure of Heusler-type NiMnIn(Co) glass-coated microwires with metallic nucleus diameters ranging from 13 up to 23 µm and total diameters from 47 to 55 µm by prepared by the Taylor-Ulitovsky technique.

Tailoring the High-Frequency Giant Magnetoimpedance Effect of Amorphous Co-Rich Microwires

We studied the giant magnetoimpedance (GMI) effect and magnetic properties of amorphous Co-rich magnetic microwires prepared by the Taylor-Ulitovski technique. The magnetic field dependence of impedance and the magnetic anisotropy fields can be tailored through the magnetoelastic anisotropy by controllable change of the internal stresses. Co-rich microwires exhibit high (above 300) GMI effect even at gigahertz frequencies. Features of the high-frequency GMI effect were analyzed using a ferromagnetic resonance-like approximation.

Effect of Nanocrystallization on Magnetic Properties and GMI Effect of Fe-rich Microwires

We studied the giant magnetoimpedance (GMI) effect and magnetic properties of Finemet-type FeCuNbSiB microwires. We observed that the GMI effect and magnetic softness of glass-coated microwires produced by the Taylor–Ulitovski technique can be tailored by controlling the magnetoelastic anisotropy of as-prepared FeCuNbSiB microwires, and can also be considerably improved either by heat treatment and/or choosing the suitable fabrication conditions. We observed a considerable magnetic softening of the microwires after the appropriate annealing. This magnetic softening correlates with the devitrification of amorphous samples. Amorphous Fe-rich microwires exhibited a low GMI effect (GMI ratio below 5%). A considerable enhancement of the GMI effect (GMI ratio up to 100%) has been observed in heat-treated microwires with nanocrystalline structure.

Tuning of Magnetic Properties and GMI Effect of Co-Based Amorphous Microwires by Annealing

We studied the effect of annealing on the giant magnetoimpedance (GMI) effect, magnetic domain wall dynamics, and magnetic properties of amorphous iron (Fe) and cobalt (Co)-based microwires prepared by the Taylor–Ulitovsky technique. We observed that the properties can be tailored by controlling the magnetoelastic anisotropy of CoFeBSiC microwires during wire formation and also controlling the magnetic anisotropy by further heat treatment. A high GMI effect has been observed in the as-prepared Co-based microwires. High domain wall velocity and rectangular hysteresis loops have been observed in additionally heat-treated microwires. We observed increasing of the wall velocity under stress in some annealed samples. We demonstrated that, for certain annealing conditions, we can observe coexistence of the GMI effect and magnetic domain wall propagation in the same sample.

Optimization of Magnetic Properties and Giant Magnetoimpedance Effect in Nanocrystalline Microwires

We studied giant magnetoimpedance (GMI) effect, magnetic, and magneto-optic properties of Finemet-type FeCuNbSiB microwires. We observed that GMI effect and magnetic softness of glass-coated microwires produced by the Taylor-Ulitovsky technique can be tailored either controlling magnetoelastic anisotropy of as-prepared FeCuNbSiB microwires or controlling their structure either by heat treatment or changing the fabrication conditions. We observed considerable magnetic softening of studied microwires after annealing. This magnetic softening correlates with the devitrification of amorphous samples. Amorphous Fe-rich microwires exhibited low GMI effect (GMI ratio below 1 %). Considerable enhancement of the GMI effect (GMI ratio up to 100 %) has been observed in heat-treated microwires with nanocrystalline structure. Some of as-prepared Fe-rich magnetic microwires exhibited nanocrystalline structure and GMI ratio up to 45 %. The magneto-optical study demonstrated the existence of helical surface magnetic structure in the as-prepared microwires.

Effect of Annealing on Magnetic Properties and Giant Magnetoimpedance Effect of Amorphous Microwires

We report on the magnetic properties and giant magnetoimpedance (GMI) effect of amorphous glass-coated Co-rich microwires in as-prepared and annealed states. The magnetic field and frequency dependences of GMI, magnetic hysteresis loops, and domain wall (DW) dynamics of Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">69.2</sub> Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4.1</sub> B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11.8</sub> Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">13.8</sub> C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1.1</sub> microwires produced by the Taylor-Ulitovski technique were investigated systematically. We have shown that these properties can be tailored either by controlling magnetoelastic anisotropy of the as-prepared microwires or by controlling their magnetic anisotropy via proper annealing. While the GMI effect has been achieved in an as-prepared microwire, high DW velocity and rectangular hysteresis loops have been observed in its annealed counterpart.

Effect of Nanocrystallization on Magnetic Properties and GMI Effect of Microwires

We studied giant magnetoimpedance (GMI) effect and magnetic properties of FINEMET-type FeCuNbSiB microwires. We observed that the GMI effect and magnetic softness of glass-coated microwires produced by the Taylor-Ulitovski technique can be tailored either controlling magnetoelastic anisotropy of as-prepared FeCuNbSiB microwires or controlling their structure by heat treatment or changing the fabrication conditions. We observed considerable magnetic softening of studied microwires after annealing. This magnetic softening correlates with the devitrification of amorphous samples. Amorphous microwires exhibited low GMI effect (GMI ratio below 5%). Considerable enhancement of the GMI effect (GMI ratio up to 100%) has been observed in heat treated microwires with nanocrystalline structure. Some of as-prepared Fe-rich exhibited nanocrystalline structure and the GMI ratio up to 45%.

Effect of nanocrystallization on giant magnetoimpedance effect of Fe-based microwires

We studied giant magnetoimpedance (GMI) effect and magnetic properties of Fe70.8Cu1Nb3.1Si14.5B10.6 and Fe71.8Cu1Nb3.1Si15B9.1 Finemet microwires. We observed that GMI effect and magnetic softness of glass-coated microwires produced by the Taylor–Ulitovski technique can be tailored either controlling magnetoelastic anisotropy of as-cast FeCuNbSiB microwires, and/or controlling their structure by heat treatment or by changing the fabrication conditions. High GMI effect has been observed in as-prepared Fe-rich and heat treated microwires with nanocrystalline structure.

Magnetic properties of Ni-Mn-In-Co Heusler-type glass-coated microwires

We report on fabrication and magnetic properties of Heusler-type NiMnInCo glass-coated microwires with metallic nucleus diameters, d, from 13 up to 23 μm and total diameters, D, from 47 to 55 μm by the Taylor-Ulitovsky technique. Considerable dependence of magnetization on magnetic field below and in vicinity of Curie temperature can be related with two-phase structure or with the Hopkinson effect.

Optimization of the giant magnetoimpedance effect of Finemet-type microwires through the nanocrystallization

We studied correlation of magnetic properties, giant magnetoimpedance (GMI) effect and structure of Finemet-type glass-coated microwires obtained by the Taylor-Ulitovski technique. We observed considerable magnetic softening and increasing of the GMI ratio, ΔZ/Z, (from 3% up to 100%) after annealing of studied microwires. On the other hand, even in as-prepared Fe73.8Cu1Nb3.1Si13B9.1 microwire, we observed existence of α-Fe nanocrystallites with average grain size about 12 nm and considerable GMI effect (ΔZ/Z up to 50%).

High Frequency Giant Magnetoimpedance Effect of amorphous microwires for magnetic sensors applications

Abstract We studied the Giant magnetoimpedance (GMI) effect and magnetic properties of amorphous Fe-Co rich magnetic microwires prepared by the Taylor-Ulitovski technique. We observed that these properties can be tailored either controlling magnetoelastic anisotropy of as-prepared Co-rich microwires or controlling their magnetic anisotropy by heat treatment. High GMI effect even at GHz frequencies has been observed in Co-rich microwires.