Stability studies in Fe-Ni based amorphous ribbons: Some refinement

A new method for stability tests of thin hyperquenched materials (amorphous ribbons, thin films) has been reported. It consists of measuring the changes in the resistivity of the material under high current density. The structural evolution is so perfectly revealed that various characteristics can be exhibited. In particular, an energy coefficient of resisistivity (ECR) and an energy coefficient of stability (ECS) are measured. We describe here how, by taking into account the section of the sample, we obtained a normalisation of these two coefficients per unit mass and section. The intrinsic characteristic stability of hyperquenched material is hence better specified. The results here are obtained on amorphous Fe80-xNixB12Si8ribbons. We show that this method is perfectly adapted for revealing quantitatively the beneficial effect of Fe on stability for the compositions studied.