Temperature, stress, and structural-relaxation dependence of the magnetostriction in (Co0.94/BFe0.06)75/BSi15B10 glasses

High-sensitivity measurements of the magnetostriction constant λs have been performed in the nearly zero magnetostriction (Co0.94Fe0.06)75Si15B10 metallic glass as a function of the stress and temperature after pulse-annealing treatments. A stress dependence of λs in this amorphous alloy is reported for the first time. At room temperature a slope of about -2×10-7 GPa-1 has been determined leading to a change in the sign of the magnetostriction constant in some circumstances. For determination of the thermal variation of λs, the temperature was changed by means of the alternating current flowing through the sample during the measurement, which was done by the small-angle magnetization-rotation (SAMR) method. The compensation temperatures, i.e., those temperatures at which the value of λs vanishes in going from negative to positive, were determined after isochronal annealing. In this way, the evolution of the single-ion and two-ion contributions to the magneto- striction was monitored during the structural relaxation. The ratio between the two contributions follows a chemical short-range-order kinetics. The stress dependence of the single-ion and two-ion contributions was deduced from measurements of the stress dependence of the magnetostriction at different temperatures.