High-frequency magnetoimpedance properties in FINEMET-type ribbons with a Cu-Co electrodeposited layer

SILVEYRA JOSEFINA M; COÏSSON MARCO; CELEGATO FEDERICA; TIBERTO PAOLA; VINAI FRANCO; CREMASCHI VICTORIA J; MURACA DIEGO; MOYA JAVIER A; SIRKIN HUGO R M

Buenos Aires

Congreso; 15th International Symposium on Metastable, Amorphous and Nanostructured Materials; 2008

The large change of the impedance in soft magnetic alloys submitted to an external magnetic field has opened a new branch in research. This is due to possible applications as magnetic sensors already in market and because of the extensive use of giant magnetoimpedance as a tool to investigate intrinsic and extrinsic magnetic properties of soft magnetic materials. A comprehensive analysis of magnetoimpedance phenomena in FINEMET-type as spun ribbons with a Cu-Co layer electrodeposited at different currents is presented here as a function of microstructure. The measurements were performed in moderate and high frequencies (30 kHz–6 GHz) under an axial magnetic field H, up to 2500 A/m. The magnetoimpedance variations have been studied by measuring the reflection parameter S11 of a coaxial line containing the magnetic sample by means of a vectorial network analyzer. The GMI vs. applied field curve does not show a monotonically decay but displays a maximum. GMI first rises with frequencies up to 10 MHz reaching values of Z/Zmax20%. With increasing frequencies the GMI ratio is seen to decrease becoming vanishingly small at f 1 GHz.