Temperature Distribution In A Joule Effect Annealed Amorphous Glasscovered

We present results on the Joule effect heating of amorphous glass-covered magnetic wires. A simple theoretical model that allows us to determine the radial distribution of temperature in an amorphous glass-covered wire subjected to Joule effect annealing is presented. The experimental verification of the model was performed on Feyv.jSiy.sBis amorphous glass-covered wires by measuring the temperature dependence of the electrical resistance for a furnace annealed sample and the dependence of resistance on the annealing current for a Joule heated sample. © 1999 Trans Tech Publications.302-303239243Chiriac, H., Ovâri, T.-A., (1996) Prog. Mater. Sci., 40, p. 333Chiriac, H., Ovari, T.-A., Pop, Gh., Barariu, F., (1997) J. Appl. Phys., 81, p. 5817Knobel, M., Allia, P., Gômez-Polo, C., Chiriac, H., Vâzquez, M., (1995) J. Phys. D: Appl. Phys., 2, p. 2398Chiriac, H., Astefanoaei, I., (1996) Phys. Stat. Sol. (A), 153, p. 18

Role Of Soft Magnetic Properties On The Sensitivity Of The Giant Magneto-impedance Effect

We present results on the giant magneto-impedance effect in amorphous and nanocrystalline wires, glass-covered wires, and ribbons. The analysis of the experimental data shows that improvements in the soft magnetic properties of such materials compensate the absence of suitable domain structures, usually required for a sensitive magneto-impedance response. The magneto-impedance effect in nanocrystalline materials is in some cases larger than in amorphous ones with favorable magnetic structures. © 1999 Trans Tech Publications,.302-303234238Panina, L.V., Mohri, K., Uchiyama, T., Bushida, K., Noda, M., (1995) Nanostructured and Non-Crystalline Materials, p. 461. , edited by M. Vâzquez and A. Hernando World Scientific, SingaporePanina, L.V., Mohri, K., Bushida, K., Noda, M., (1994) J. Appl. Phys., 76, p. 6198Chiriac, H., Vinai, F., Ovâri, T.-A., Marinescu, C.S., Barariu, F., Tiberto, P., (1997) Mat. Sei. Eng. a, 226-228, p. 646Knobel, M., Chiriac, H., Sinnecker, J.P., Marinescu, S., Ovâri, T.-A., Inoue, A., (1997) Sensors and Actuators A: Physical, 59, p. 256Chiriac, H., Pop, Gh., Ovâri, T.-A., Barariu, F., (1996) IEEE Trans. Magn., 32, p. 4872Chiriac, H., Ovâri, T.-A., Pop, Gh., Barariu, F., (1997) J. Appl. Phys., 81, p. 581

Controlling depinning and propagation of single domain-walls in magnetic microwires

The magnetization reversal in magnetostrictive amorphous microwires takes place by depinning and propagation of a single domain wall. This is a consequence of the particular domain structure determined by the strong uniaxial anisotropy from the reinforcement of magnetoelastic and shape contributions. In the present study, after an overview on the current state-of-the art on the topic, we introduce the general behaviour of single walls in 30 to 40 cm long Fe-base microwires propagating under homogeneous field. Depending on the way the walls are generated, we distinguish among three different walls namely, standard wall, DWst, depinned and propagating from the wire’s end under homogeneous field which motion is the first one to switch on; reverse wall, DWrev, propagating from the opposite end under non-homogeneous field, and defect wall, DWdef, nucleated around local defect. Both, DWrev and DWdef are observed only under large enough applied field. In the subsequent section, we study the propagation of a wall under applied field smaller than the switching field. There, we conclude that a minimum field, Hdep,0, is needed to depin the DWst, as well as that a minimum field, Hprop,0, is required for the wall to propagate long distances. In the last section, we analyse the shape of induced signals in the pickup coils upon the crossing of the walls and its correlation to the domain walls shape. We conclude that length and shape of the wall are significantly distorted by the fact that the wall is typically as long as the measuring coils