THE EFFECT OF ANNEALING AND CRYSTALLIZATION ON THE MAGNETOELASTIC PROPERTIES OF CO-SI-B AMORPHOUS WIRES

The field dependence of Young's modulus (Delta E effect) of amorphous wires of Co72.5Si12.5B15 has been studied in the as-quenched state, an d after annealing for times between one and several hundred minutes at temperatures of 450, 480, and 500 degrees C. In the as-quenched state the Delta E effect is small (<2%), because the quenching stresses cou ple with the magnetostriction (lambda(s) similar to-3X10(-6)) to produ ce significant anisotropy. Annealing for short times (>1 min) is suffi cient to relieve much of the quenching stress, resulting in magnetic s oftening and enhanced Delta E effect (at best >30%). Further annealing eventually reverses these trends, increasing coercivity and anisotrop y, and reducing the Delta E effect. This behavior is attributed to sur face crystallization. The results are interpreted in terms of the core -shell domain model, and are consistent with the retention of a signif icant component of circumferential domain structure in the shell in al l annealing conditions studied. (C) 1996 American Institute of Physics .