High-frequency responses of granular CoFeHfO and amorphous CoZrTa magnetic materials

Abstract

High-resistivity soft magnetic materials are receiving much attention as they have relatively low core loss at high frequencies. We developed magnetically soft granular CoFeHfO material by pulsed-dc reactive magnetron sputtering and compared its electrical and magnetic properties, especially permeability spectra, with those of amorphous CoZrTa material. We also investigated the permeability spectra of patterned CoFeHfO films with different thicknesses and observed their magnetic domain structures by Kerr imaging microscopy. The granular CoFeHfO material has a better high-frequency response than the amorphous CoZrTa at thicknesses beyond ∼0.5μm, if the ratio of the real/imaginary parts of the permeability is the principal figure of merit, and is an excellent candidate for high-frequency applications such as integrated magnetic inductors.

High-frequency signal processing using magnetic layered structures

“…Noise suppression, for example, can be accomplished by using low-conductivity metallic materials with lower M s values [11][12][13]. These materials are primarily useful in the 1-10 GHz range.…”

Integrated Microstrip Lines With Co–Ta–Zr Magnetic Films

“…The latter adds up with the 0018-9464/$25.00 © 2008 IEEE on this material are further discussed in [5], [17].…”

“…The magnetic film consists of amorphous Co-Ta-Zr with a relatively high resistivity [5], [17], which translates into a large skin depth when used as a magnetic core for on-chip passives. The latter allows for the integration of a relatively thick (1 m) magnetic film, leading to an order of magnitude increase in the microstrip inductance per unit length when compared to nonmagnetic devices.…”

Numerical simulation on the noise suppression effect of nanogranular magnetic film CoFeHfO on PCB transmission lines

“…In this study, we simulated the noise suppression effects of nanogranular soft magnetic film CoFeHfO on both MSL and CPW up to 10 GHz. CoFeHfO has a high permeability (~150) and electrical resistivity (~1600 μcm) [8], which are good for high-frequency noise absorption. In our simulation, the measured permeability spectra of CoFeHfO film on a PCB were used, which made the modeling realistic and the results reliable [9].…”