Performance of Crossed Anisotropy Multilayered CoZrNb Films as IC Chip Level Electromagnetic Noise Suppressor

Co-Zr-Nb multilayers with crossed anisotropy along with multilayers with uniaxial anisotropy were investigated from the standpoint of electromagnetic noise suppressors. Frequency dependences of conduction losses and magnetic near field intensity of a microstrip line (MSL) covered with these multilayers were measured simultaneously. It was found that ferromagnetic resonance excited by RF field from MSL takes a major role of noise suppression over a wide frequency. The ferromagnetic resonance frequency is determined by intrinsic anisotropy field. In addition, shape anisotropy field caused by presence of MSL is negligibly small. The in-plane isotropy feature of noise suppressing performance for the crossed anisotropy films was verified experimentally and numerically.