Angular dependence of resonant absorption in FeCoB synthetic antiferromagnets

Abstract

Magnetization dynamics in a series of FeCoB/Ru/FeCoB coupled samples were investigated using a critical-curve-like approach through angular dependent broadband microwave absorption spectroscopy. Two samples were selected in this study, with ferromagnetic and antiferromagnetic coupling between the FeCoB layers. The dynamic critical curves (DCC) were obtained by systematically probing the angular-dependent FMR absorption at selected frequencies for both samples to show the effect of layer coupling both as a function of frequency and of angle. The DCC representation has the advantage of offering a direct and complete visual representation of anisotropy, interactions, and magnetization dynamics effects. The DCC is compared with static critical curve measured using a reversible susceptibility experiment