Giant Magneto-Impedance Effect in Ni$_80$Fe$_20$Composite Multilayers

The giant magneto-impedance (GMI) effect of (NiFe/SiO
$_2$
)
$_ n$
/Cu/(SiO
$_2$
/NiFe)
$_ n$
composite multilayers is investigated. The results show that the magnitude of the GMI effect changes with an increasing number of layers
$n$
of bilayers SiO
$_2$
/NiFe. At
$n = 3$
, the maximum MI ratios reached 17.08%. When
$n$
was further increased to four and five, the MI ratios decreased slightly. This is mainly attributed to changes in the samples' magnetic characteristics, which is due to the influence of the magnetic moment direction of the NiFe layer and the inner stress.