Given that the magnetoinductive effect (MI), skin effect and ferromagnetic resonance influence magnetic permeability behavior at different frequency ranges, the description of the magnetoimpedance effect over a wide range of frequency becomes a difficult task. To that end, we perform an experimental investigation of the magnetoimpedance effect in a tri-layered thin film over a wide frequency range. We compare the experimental results for a tri-layered thin film with numerical calculus performed using an approach that considers a magnetic transverse susceptibility model for planar systems and an appropriate magnetoimpedance model for a tri-layered system together. The results show remarkably good agreement between numerical calculus and experimental measurements. Thus, we discuss the experimental results in terms of different mechanisms that govern the MI changes observed in distinct frequency ranges and provide experimental support to confirm the validity of the theoretical approach. V

No abstract

We investigate the magnetization dynamics in low damping parameter α systems by measuring the magnetoimpedance effect over a wide range of frequencies, from 0.1 to 3.0 GHz, in Co2FeAl/Au/Co2FeAl full-Heusler alloy trilayer films grown by magnetron sputtering on glass and MgO substrates. We show that the film produced on the glass substrate presents high magnetoimpedance performance, while that grown on the MgO substrate has low magnetoimpedance performance. Since both films are polycrystalline and have isotropic in-plane magnetic properties, we interpret the magnetoimpedance results in terms of the low damping parameter α and strain effects in the films. Thus, we verified that our films present good magnetoimpedance performance and showed that high performance can be achieved even in films with isotropic in-plane magnetic properties, since they present low damping parameter α.

No abstract

We report a systematic study of the structural and quasi-static magnetic properties, as well as of the dynamic magnetic response through MI effect, in Co2FeAl and MgO//Co2FeAl single layers and a MgO//Co2FeAl/Ag/Co2FeAl trilayered film, all grown onto an amorphous substrate. We present a new route to induce the crystalline structure in the Co2FeAl alloy and verify that changes in the structural phase of this material leads to remarkable modifications of the magnetic anisotropy and, consequently, dynamic magnetic behavior. Considering the electrical and magnetic properties of the Co2FeAl, our results open new possibilities for technological applications of this full-Heusler alloy in rigid and flexible spintronic devices.