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Mg1–xCuxFe2O4 ferrites for electromagnetic interference suppression were systematically investigated in crystallographic structure, morphologies, and magnetic and dielectric spectra over a frequency range of 10–1000 MHz. Findings indicated that the Mg1–xCuxFe2O4 ferrites with $x$ = 0–0.6 showed a single-phase cubic spinel structure, but the sample structure with $x = 0.8$ transforms into a tetragonal phase. Moreover, the substitution of Cu was shown to lower the sintering temperature and enhance densification of the ferrites, resulting in increased saturation magnetization (67%) and decreased coercivity (88%). More importantly, the complex permeability and permittivity of Mg–Cu ferrites could be tailored with Cu content, leading to an enhanced magnetic loss and permeability. The magnetic loss tangent of the Mg0.4Cu0.6Fe2O4 ferrite sintered at 1150 °C was significantly increased by 56% at $f>300$ MHz. [ABSTRACT FROM AUTHOR]

The fabrication and high-frequency ferromagnetic performances of (Fe50Co50)1-x(Al2O3)x soft magnetic films (SMFs) were investigated. It is revealed that the modified composition gradient sputtering method dramatically improves the high-frequency soft magnetic properties of the as-prepared films. This method gives rise to a linearly increased distribution of compositions and residual stress. As a result, comparing with the samples prepared by conventional composition gradient sputtering (CGS) method, a very high and uniform ferromagnetic resonance frequency in excess of 5 GHz, high uniaxial magnetic anisotropic field, and low magnetic loss were obtained, which are particularly in favor of the integration between magnetic films and radio-frequency (RF) components. [ABSTRACT FROM AUTHOR]