Amorphous glass-covered magnetic wires: Preparation, properties, applications

The main magnetic characteristics regarding the domain structure and magnetization processes (axial, circular and Matteucci and inverse Wiedemann effects) of amorphous wires and glass-coated microwires are analysed. Magnetic bistability, spontaneously observed in samples with large enough ratio magneto-elastic anisotropy with axial easy axis to shape anisotropy, is the main source for a number of sensor applications in pulse generators, position and field sensors, encoded security tags, rotational counters, magnetostrictive delay lines, and so on. The relevant perspectives of the novel giant magneto-impedance effect recently reported and observed in non-magnetostrictive samples are also introduced.

https://iopscience.iop.org/article/10.1088/0022-3727/29/4/001/pdf

A soft magnetic wire for sensor applications

Ferromagnetic microwires enabled multifunctional composite materials

Amorphous wires and their applications

We evaluate, using exact general formulas, the flux-metric and magnetometric demagnetizing factors, N/sub f,m/, of a rectangular prism of dimensions 2a/spl times/2b/spl times/2c with susceptibility /spl chi/=0 and the demagnetizing factor, N, of an ellipsoid of semiaxes a, b. and c along the c axis. The results as functions of longitudinal and transverse dimension ratios are listed in tables and plotted in figures. The three special cases of b/spl Gt/(ca)/sup 1/2/, b/spl Lt/(ca)/sup 1/2/, and a=b are analyzed together with the general case, to quantitatively show the validity of approximate formulas for special cases. N/sub f,m/ of prisms with any given values of /spl chi/ may be estimated to an accuracy about 10%, since 1) N/sub f,m/ of prisms with a=b are very near those of cylinders, for which the /spl chi/ dependence has been calculated quite completely; 2) the /spl chi/ dependence of the transverse N/sub f,m/ of prisms with b=/spl infin/ (rectangular bars) have recently been calculated completely; and 3) N/sub f,m/(X=/spl infin/) for prisms of great longitudinal dimension ratios are close to N of the corresponding ellipsoids. Thus, the existing very incomplete results can be used in some cases satisfactorily, although much work has to be done before the actual /spl chi/ dependence of N/sub f,m/ is available as it is for cylinders.

Demagnetizing factors of rectangular prisms and ellipsoids

Influence of the sample length on the switching process of magnetostrictive amorphous wire

Magnetic properties of amorphous and devitrified FeSiBCuNb glass-coated microwires

Structural relaxation and magnetic properties of Co-rich amorphous wire

Hysteresis loops and domain structure of as-cast Fe-rich and stress-annealed low magnetostrictive Co-rich bistable wires have been investigated as functions of the distance to the end of wires with different lengths. From the analysis of the changes of the squareness ratio and differential susceptibility at remanence, the existence of conical closure domains at the ends to decrease the magnetostatic energy is inferred. The switching process is accompanied by a sudden reconstruction of the domain structure. >

C. Gómez-Polo

Papers

Influence of the sample length on the switching process of magnetostrictive amorphous wire

Magnetic properties of amorphous and devitrified FeSiBCuNb glass-coated microwires

Structural relaxation and magnetic properties of Co-rich amorphous wire

Switching mechanism and domain structure of bistable amorphous wires

Stress induced magnetic anisotropy in non-magnetostrictive amorphous wires