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

JOSEFINA M. SILVEYRA; MARCO COÏSSON; FEDERICA CELEGATO; PAOLA TIBERTO; FRANCO VINAI; JAVIER A. MOYA; VICTORIA J. CREMASCHI

JOURNAL OF ALLOYS AND COMPOUNDS

ELSEVIER SCIENCE SA

Año: 2009 vol. 495 p. 412 - 416

0925-8388

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, up to 25 kA/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 vector network analyzer. The GMI vs applied field curve does not show a monotonic decay but displays a maximum. GMI first increases with frequencies up to ∼10MHz reaching values of Z/Zmax ∼20%. At higher frequencies the GMI ratio is seen to decrease becoming vanishingly small at ∼1 GHz.