High-frequency properties of FeCoSiB thin films with crossed anisotropy

Investigations on amorphous FeCoSiB/SiO₂/FeCoSiB thin-film samples with crossed anisotropies are presented in this paper. The samples consist of two magnetic layers, 40 nm thick each, where the second magnetic layer´s uniaxial anisotropy is rotated by an angle of 90° with respect to the anisotropy of the first layer. The individual layers were separated by a 20 nm SiO₂ thin film. The angular dependent magnetic properties of the samples have been characterized by vibrating sample and inductive magnetometry. The high-frequency (HF) response was determined by HF-permeameter measurements and pulsed inductive microwave magnetometry (PIMM). Good HF-response independent of the magnetic field excitation angle is achieved. The results are compared to an 80 nm FeCoSiB reference film with uniaxial anisotropy. Our results provide new insights important for the design of HF magnetic devices.