Magnetic properties and giant magnetoimpedance effect of FINEMET/Fe₅₀Pt₅₀ composite ribbons

In order to study the magnetic properties and giant magnetoimpedance (GMI) effect of FINEMET/Fe₅₀Pt₅₀ composite ribbons. A series of Fe₅₀Pt₅₀ films with different thickness (t) were deposited onto FINEMET ribbons by magnetron sputtering. The results showed that all FINEMET/Fe₅₀Pt₅₀ composite samples maintain good soft magnetic properties. The anisotropy field decreases firstly and then increases with the increasing of Fe₅₀Pt₅₀ layer thickness (0 ~ 117 nm). When the coating thickness is 98 nm, FINEMET/Fe₅₀Pt₅₀ composite samples obtain the smallest coercivity field (0.04 Oe). Its GMI ratio is 122%, which is three times higher than the FINEMET ribbon itself. This clearly indicates that addition of the Fe₅₀Pt₅₀ layer can impact magnetic properties and significantly enhance the GMI ratio, which is analyzed in terms of exchange coupling and dipole interaction between the FINEMET ribbon and coating film. We believe that these results provide a good guidance for GMI effect of soft magnetic amorphous composite materials with high sensitivity magnetic sensors.