Study On The Preparation And Magnetic Properties Of The Composite Wires With Anti-ferromagnetic Layer

The giant magneto-impedance effect (GMI) is one of the hottest research points in recent years for its small size, ultra-high sensitivity and high cost performance. An autobiased linear field sensor may be produced with the use of exchange biased MI elements. Due to the exchange bias effect can induce asymmetric GMI effect (AGMI) with no other power consuming around zero field. Currently, only a few studies have focused on this work using planar thin film systems. In this paper, Fe₅₀Mn₅₀/Ni₈₀Fe₂₀/Cu, Ni₈₀Fe₂₀/Fe₅₀Mn₅₀/Cu and Ni₈₀Fe₂₀/Fe₅₀Mn₅₀/Ni₈₀Fe₂₀/Cu composite wires were prepared by magnetron sputtering. The experimental conditions and the influence of the Fe₅₀Mn₅₀ layer on the composite wires'magnetic properties and GMI effect were studied.1. The influence of the experimental conditions on the composite wires' magnetic properties were studied from the following four aspects.â‘ Ni₈₀Fe₂₀/Cu composite wires with faster spin speed during deposition could enhance GMI effectâ‘¡GMI effect of the Ni₈₀Fe₂₀/Fe₅₀Mn₅₀/Cu composite wire was enhanced by reducing the spin rate during depositing the Fe₅₀Mn₅₀ layer.â‘¢GMI effect of the Fe₅₀Mn₅₀/Ni₈₀Fe₂₀/Cu composite wires could also be changed by increasing the time between sputtering the Ni₈₀Fe₂₀ layer and Fe₅₀Mn₅₀ layer.â‘£The MI ratio of the Fe₅₀Mn₅₀/Ni₈₀Fe₂₀/Cu composite wires and the NisoFe2o/ Fe₅₀Mn₅₀/Cu composite wires were repeated measured. If the anti-ferromagnetic layer had no effect on the composite wires' MI ratio, the repeated measurements were the same as the first. If the anti-ferromagnetic layer had effect on the composite wires'MI ratio, there were difference between the repeated measurements and the first.2. The Fe₅₀Mn₅₀/Ni₈₀Fe₂₀/Cu, Ni₈₀Fe₂₀/Fe₅₀Mn₅₀/Cu and Ni₈₀Fe₂₀/ Fe₅₀Mn₅₀/Ni₈₀Fe₂₀/Cu composite wires were prepared by magnetron sputtering. The influence of the thickness of the Fe₅₀Mn₅₀ layer on the composite wires'magnetic properties and GMI effect were studied.â‘ The appropriate thickness of the Fe₅₀Mn₅₀ layer can change the internal Ni₈₀Fe₂₀ layer's magnetic structure, making the magnetic structure of the Fe₅₀Mn₅₀/Ni₈₀Fe₂₀/Cu composite wires tend to the vertical. The maximum MI ratio of the composite wires decreases with the thickness of the Fe₅₀Mn₅₀ layer.â‘¡The appropriate thickness of Fe₅₀Mn₅₀ layer can reduce the coercivity of the Ni₈₀Fe₂₀/Fe₅₀Mn₅₀/Cu composite wires and enhance the MI ratio.â‘¢When the thickness of the Fe₅₀Mn₅₀ layer increases, the MI ratio of the Ni₈₀Fe₂₀/Fe₅₀Mn₅₀/Ni₈₀Fe₂₀/Cu composite wires increases firstly and then decreases. This is mainly due to the appropriate thickness of Fe₅₀Mn₅₀ layer can improve the soft magnetic properties of the outer ferromagnetic layer and increase the MI ratio. And AGMI effect is appear.