Magnetization-affected localized flows in ferromagnetic metallic glass

Abstract

In this paper, the interaction between magnetization and dynamic relaxation of heterogeneous structure in a ferromagnetic metallic glass (MG) is investigated. It is found that the magnetic state of the MG can be changed through wearing its surface. Accompanying with the change of magnetic state, the local dynamic mechanical behavior of the MG was detected by nanoindentation varies. Through analyzing with combination of the three-parameter viscoelastic model and state-transition theory, it is discovered that the microstructure of the glass can be apparently changed by magnetization with the effective size, viscosity of the liquid-like cores and the relaxation time increased by more than 3 times. Inversely, with cycling loading below the elastic limit of the MG using nanoindentation, it is revealed that localized flows of nano-liquid in the glass erase the effect of magnetization. The interaction between magnetization and localized flows relates to spin-orbit coupling in the MG; the change of magnetic state and liquid-like regions in the MG does not affect its instantaneous shear modulus associated with its ideal glassy state. The studies help understand the dynamic magneto-mechanical properties of amorphous magnetic materials, and have technological importance for their applications.