High Frequency Magnetoimpedance of FeNi/Cu/FeNi Sensitive Elements with Different Geometries

Abstract

Abstract. In this work magnetoimpedance (MI) behaviour was studied experimentally for Fe 19 Ni 81 (175 nm)/Cu(350 nm)/Fe 19 Ni 81 (175 nm) sensitive elements deposited by rf-sputtering. A constant magnetic field was applied in plane of the sandwiches during deposition perpendicular to the Cu-lead in order to induce a magnetic anisotropy. Sandwiches with different width (w) of FeNi parts were obtained. The complex impedance was measured as a function of the external magnetic field for a frequency range of 1 MHz to 700 MHz for MI elements with different geometries. Some of MI experimental data are comparatively analysed with finite elements numerical calculations data. The obtained results can be useful for optimization of the design of miniaturized MI detectors. IntroductionMagnetoimpedance (MI) is the change of the high frequency impedance of a soft ferromagnet under application external magnetic field [1][2][3][4]. Mathematical description of the magnetoimpedance phenomenon requires analytical solution of the Maxwellґs equations that can be done only for simplest geometries and using approximations [5][6][7]. For example, analytical solution is impossible in case of MI sandwiched structure ferromagnet/conductor/ferromagnet for narrower central conductive part. The finite elements method (FEM) was proposed as useful numerical method for complex geometry of MI sensitive elements [8][9].In this work the longitudinal MI behaviour was studied for

Temperature Dependence of Magnetoimpedance in FeNi/Cu/FeNi Film Structures with Different Geometries

“…The magnetoimpedance effect (MI) is a change of the complex impedance of a soft ferromagnetic conductor under application of an external magnetic field [1][2][3][4]. The sensitivity of MI to a magnetic field was observed to be of the order of 500 %/Oe in amorphous ribbons [5].…”