Dependence of the Magnetic Properties of an Amorphous Metal Alloy on Its Nanoporosity

Magnetic and structural properties of an amorphous alloy based on iron are investigated. The properties and state of the alloy are changed under hydrostatic pressure of up to 1.3 GPa. An increase in the pressure leads to a linear increase in the maximum magnetic induction and a linear decrease in the remanence. Two nanopore fractions with average sizes of ∼20 and 150 nm are revealed in the alloy with the use of small-angle x-ray diffraction. The application of the pressure decreases the size of nanopores and increases the average distance between their boundaries, i.e., increases the average sizes of continuity regions in the alloy. It is established that the relative change in the magnetic characteristics is linearly related to the change in the size of the continuity regions in the alloy. Upon extrapolation to zero nanoporosity, the remanence reduces to zero. The inference is made that the nanopores play a dominant role (as compared to other structural defects) in the magnetic properties of the alloy.