X-Ray Transmission Microscopy of Dipolar-Coupled Bilayers with Crossed Anisotropies for Reconfigurable Spin Wave Transport

Scanning transmission X-ray magnetic resonant microscopy (STXMRM) is used to study the magnetization reversal mechanisms of its stripe domains in dipolar-coupled layers
$\mathbf{Py}/\mathbf{Al/NdCo}_{7}$
, used for reconfigurable spin wave transport. The element specificity of X-rays permitted to observe the evolution of the stripe-domains as a function of the external magnetic field in each layer and determine the correlations between layers. This is key for the understanding of the hysteretic behavior observed in the spin wave transmission of the permalloy (Py) when it is dipolar coupled to the stripe domain textured
$\mathbf{NdCo}_{7}$
layer. The images obtained show that the stripe domain imprinting on the Py layer is undetected in the range of fields where hysteretic properties in the dynamics of the Py magnetic moments are present. Therefore, the spin dynamics in the Py should be governed by the stray field of the
$\mathbf{NdCo}_{7}$
layer.