Application of Matteucci Voltage Pulses of Amorphous Wires in Sensing Both Direction and Magnitude of Twist

In this work the effect of torsion on the Matteucci voltage pulses in amorphous wires has been studied. It has been shown that: Amplitude of the pulses decreases to zero at a twist angle that depends on the chemical composition of the wire. From zero torsion, the amplitude of the Matteucci voltage increases when the wires are twisted counter-clockwise. However, when the wires are twisted clockwise, the amplitude of the Matteucci voltage pulses decreases up to a minimum point (zero) before, finally, starting to increase. This is a clear distinction (in behaviour) between clockwise and counter-clockwise torsion, which can be employed to determine the direction of initial twist. Also, the low torsion region of the torsion-Matteucci voltage characteristic shows a clear possibility of employing the stress sensitive Matteucci voltage to determine the magnitude of torsion. The Matteucci voltage is quite sensitive to the torsion. It is thus expected to provide high sensitivity for measurement of torsion in the “low and very low torsion region”. It has also been established that when the positioning of the amorphous wire in the magnetizing coil is reversed (wire ends are interchanged), the torsion-Matteucci voltage characteristic obtained is virtually a mirror image of the previous direction. For instance, if the zero amplitude Matteucci voltage was being obtained at a twist angle of 45° clockwise, it will now be obtained at an angle of the same magnitude, but for a counter-clockwise twist. The physics of this latter phenomenon too would be of interest to researchers of physics of magnetism. J. agric. Sci. technol. Vol.5(1) 2003: 116-12

Security Sensor System Based on Large Barkhausen Jump of Amorphous Magnetostrictive Metal Wires

This paper presents and discusses preliminary laboratory results for fabrication and testing of a security sensor system for use in article surveillance in such places as libraries, CD rental shops, and supermarkets, as a crime preventive measure. The system employs the large Barkhausen jump (LBJ) inherent in the amorphous magnetostrictive metal wires. The system takes advantage of the superior sensor characteristics of magnetostrictive metal wires. Journal of Agriculture, Science and Technology Vol.4(1) 2002: 91-10

Effect of stress on the bamboo domains and magnetization process of CoSiB amorphous wire

In this work we have studied the behavior of the bamboo domains under stress (sigma), tension (+ sigma) as well as compression (- sigma), with the aim of making the domain model of the negatively magnetostrictive (- lambda(5)) CoSiB wire clear. It is observed that the growth of the surface bamboo domains due to a has directivity depending on the orientation of the underlying core domain. In one orientation the black bamboo domain grows, while in the opposite orientation the white domain grows. From the stress behavior of the bamboo domains we have concluded that the domain model of - lambda(5) wire consists of two spiral domains of opposite rotation and proposed a new model

Dependence of magnetic properties of (Fe50Co50)(78)Si7B15 amorphous wire on the diameter

The dependence of the magnetic properties of amorphous wire on the diameter have been investigated. The anisotropy constant, hence the internal stress, of the wire increases with the wire diameter. The size of the pinned reverse domain at the wire end increases with the wire diameter. Domain observation shows that irrespective of the change in the wire diameter, the domain structure basically consists of chevron domain layer sandwiched between the surface maze domain and the inner core domain