Initial Magnetic Permeability During The Development Of The Nanocrystalline State In Amorphous Ribbons

Low-field initial permeability (μi) has been measured at several steps of nanocrystallization in four amorphous Fe73.5Cu1Nb3Si13.5B9 ribbons produced by planar flow casting with different quenching rates (QRs) from the melt. It is observed that the increase in μi upon nanocrystallization is strongly influenced by the initial free-volume content of each sample. Samples produced with higher quenching rates exhibit a faster transformation kinetics and stronger enhancement of the initial permeability in the nanocrystalline state. Conventional heat treatments and accumulative annealings were performed on all the ribbons, in order to study the effect of their inhomogeneities and induced anisotropies. © 1994.1331-3255258Yoshizawa, Oguma, Yamauchi, (1988) J. Appl. Phys., 64, p. 6044Knobel, Turtelli, Rechenberg, (1992) J. Appl. Phys., 71, p. 6008Köster, Herold, Glassy Metals I: Ionic Structure (1981) Electronic Transport and Crystallization, p. 254. , H.J. Güntherodt, H. Becker, Springer-Verlag, BerlinKnobel, Sinnecker, Saenger, Turtelli, Effect of as-cast topological disorder on the magnetic properties of nanocrystalline Fe73.5Cu1Nb3Si13.5.B9 (1993) Philosophical Magazine Part B, 68, p. 861C. Polak, M. Knobel, R. Grössinger and R. Sato Turtelli, J. Magn. Magn. Mater. (to appear)P. Allia, M. Baricco, M. Knobel, P. Tiberto and F. Vinai, IEEE Trans. Magn. (in press)Knobel, Sinnecker, Turtelli, Rechenberg, Grössinger, (1993) J. Appl. Phys., 73, p. 6603Knobel, Santos, Torriani, Turtelli, (1993) Nanostr. Mater., 2, p. 399Luborsky, (1983) Amorphous Metallic Alloys, p. 360. , F.E. Luborsky, Butterworths, Londo