402 research outputs found
Stress effect on magnetoimpedance (MI) in amorphous wires at GHz frequencies and application to stress-tunable microwave composite materials
The effect of tensile stress on magnetoimpedance (MI) in CoMnSiB amorphous
wires at microwave frequencies (0.5-3 GHz) is investigated both experimentally
and theoretically. In the presence of the dc bias magnetic field of the order
of the anisotropy field, the impedance shows very large and sensitive change
when the wire is subjected to a tensile stress: 100% and 60% per 180 MPa for
frequencies 500 MHz and 2.5 GHz, respectively. It is demonstrated that this
behavior owes mainly to the directional change in the equilibrium magnetization
caused by the applied stress and field, which agrees well with the theoretical
results for the surface impedance. This stress effect on MI is proposed to use
for creating microwave stress-tunable composite materials containing short
magnetic wires. The analysis of the dielectric response from such materials
shows that depending on the stress level in the material, the dispersion of the
effective permittivity can be of a resonant or relaxation type with a
considerable change in its values (up to 100% at 600 MPa). This media can be
used for structural stress monitoring by microwave contrast imaging
FeCuNbSiB Thin Films Deposited by Pulsed Laser Deposition: Structural and Magnetic Properties
Using the pulsed laser ablation technique, Fe73.5Cu1Nb3Si15.5B7 amorphous thin films, with smooth and uniform surfaces, have been deposited on glass and silicon substrates. Based on the information provided by the thermomagnetic analysis, the nanocrystalline state was achieved after the thermal treatment per-formed at 460 C. In nanocrystalline state, the samples present an 80 % lower coercive magnetic field and a 3.5 times higher saturation magnetization with respect to the as-deposited state.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3515
Spark Plasma Sintered NdFeB-based Nanocomposite Hard Magnets with Enhanced Magnetic Properties
Neutron diffraction studies of magnetostrictive Fe–Ga alloy ribbons
Melt-spun Fe–Ga ribbons were prepared and some ribbons were annealed at 1000 °C for 1 h then
slowly cooled to room temperature. X-ray diffraction patterns revealed no evidence of texture and
only bcc phase in the as-quenched ribbons. However, high-resolution neutron diffraction patterns
gave more information on the structure of these ribbons. Only diffractions from the disordered bcc
A2 phase were found in as-quenched ribbons with 15, 17.5, and 19.5 at. % Ga content, without any
trace of satellite peaks or splitting peaks from the proposed Ga–Ga pairing superlattice structure.
The broadening of the base of the �110� peaks for all samples except the as-quenched 15 at. % Ga
ribbon might indicate the existence of some kind of short range ordering. Ribbons developed L12
phase after annealing especially in the Fe 19.5 at. % Ga ribbon where the formation of L12 phase
reduced the Ga content in the remaining A2 phase and decreased its lattice parameter dramatically.
D03 phase formed in the as-quenched 22.5 at. % Ga ribbon and the following annealing treatment
transformed more A2 phase into D03 phase
Magnetostatic bias in multilayer microwires: theory and experiments
The hysteresis curves of multilayer microwires consisting of a soft magnetic
nucleus, intermediate non-magnetic layers, and an external hard magnetic layer
are investigated. The magnetostatic interaction between magnetic layers is
proved to give rise to an antiferromagnetic-like coupling resulting in a
magnetostatic bias in the hysteresis curves of the soft nucleus. This
magnetostatic biasing effect is investigated in terms of the microwire
geometry. The experimental results are interpreted considering an analytical
model taking into account the magnetostatic interaction between the magnetic
layers.Comment: 6 pages, 7 figure
Controlled motion of domain walls in submicron amorphous wires
© 2016 Author(s). Results on the control of the domain wall displacement in cylindrical Fe77.5Si7.5B15 amorphous glass-coated submicron wires prepared by rapid quenching from the melt are reported. The control methods have relied on conical notches with various depths, up to a few tens of nm, made in the glass coating and in the metallic nucleus using a focused ion beam (FIB) system, and on the use of small nucleation coils at one of the sample ends in order to apply magnetic field pulses aimed to enhance the nucleation of reverse domains. The notch-based method is used for the first time in the case of cylindrical ultrathin wires. The results show that the most efficient technique of controlling the domain wall motion in this type of samples is the simultaneous use of notches and nucleation coils. Their effect depends on wire diameter, notch depth, its position on the wire length, and characteristics of the applied pulse
Multimodal tretment of intracranial aneurysm
Aneurysmal subarachnoid hemorrhage (SAH), despite improvements in imagistic and medical treatment, is still a serious disease with high rates of case mortality and morbidity (40%). Technical planning and therapy options of patients with aneurismal SAH have changed during the angioCT and 3D angiography era, and long-term outcome has significantly improved during the past few decades. However, the outcome is still determined mainly by specialist experience and severity of initial bleeding or early rebleeding
Aplasia cutis congenita of the scalp- what are the steps to be followed? Case report and review of the literature
Manipulation of domain wall dynamics in amorphous microwires through the magnetoelastic anisotropy
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