TEMPERATURE DEPENDENCE OF AC INITIAL PERMEABILITY AND COMPLEX MAGNETIC CHARACTERISTICS OF AMORPHOUS RIBBONS WITH COMPOSITIONS Co_80-xFe_xB_10Si_10[x=0,2,4,6 AND 8]

摘要

Amorphous ribbons with compositons Co_80-xFe_xB_10Si_10[x=0,2,4,6 and 8] have been prepared by melt-spinning technique. Measurements of the ac initial permeability (μi) and its temperature dependence have been carried out and the ferromagnetic Curie temperature have been determined using a furnace in which the heating wire was wound in bifiller technique. The Curie temperature (Tc) increases with increasing Fe-content of these amorphous ribbons. The complex permeability Cobalt-Iron-Boron-Silicon amorphous ribbons carrying ac current has been analyzed as a function of frequency. The real and imaginary components of the complex permeability in ac conditions have been measured as a function of the instantaneous value of a Sine-wave core current density by means of an adapted LCR bridge method. Initial permeability ( μi0, frequency dependence of complex permeability and relative quality factors have been measured in the frequency range 0.5 KHz to 13 MHz for all the different compositions. The results are explained by assuming that the addition of Fe effectively lowers the magnetostriction of the amorphous Co-based ribbons in a certain range. The extraordinary increase in permeability due to the addition of Fe in the Co-based ribbons and also the increase of Tc makes the sample with composition Co_74Fe_6B_10Si_10 a good candidate for technological applications as a soft magnetic material.