Origin of magnetic switching cascades in nanostructured Co3Fe tetrapods

Abstract

We present a comprehensive study of three-dimensional arrays of nanostructured Co3Fe tetrapods consisting of four pillars each with tetrahedral symmetry, prepared by focused electron beam-induced deposition and placed in two distinct orientations with respect to the direction of an external magnetic field. Using ultra-sensitive micro-Hall magnetometry, we obtain angular-dependent magnetic stray field hysteresis loops, which reveal a characteristic yet complex magnetization reversal behavior of the structures during a field sweep. We find that micromagnetic simulations significantly deviate from the experimental findings due to inherent limitations of the method. As an alternative approach, we derive a macrospin model that enables us to elucidate the observed hysteresis curves through the cascading switching dynamics of dipolar-coupled magnetic grains.