Exchange bias effect of current Joule thermally modulatedinverted vertical (Co/Pt) n/Co/IrMn nanomultilayers br

The exchange bias has a crucial influence on the key performance parameters of magneroresistive sensor,which has wide applications in many fields. This paper presents a method that uses the Joule heating effectcombined with a magnetic field to modulate the exchange bias in magnetic multilayers. By this method, wesystematically modulate the in-plane exchange bias field (Heb) in the inverted (Co/Pt)n/Co/IrMn structure (n + 1is the repetition of the Co layers), here the thickness of the Pt layer is smaller than that of the Co layer. Inthese inverted structures, the Heb can be continuously modulated by changing the amplitude of a pulse currentIDC (an in-plane magnetic field Hp) after fixing an Hp (IDC). In more detail, the Heb deceases gradually byincreasing the IDC and its polarity of the Heb can be reversed finally, which will not disappear even under a largeIDC. Furthermore, if both the amplitude and direction of IDC (Hp) are changed, with a Hp (IDC) fixed, a reversalof Heb can be realized from positive (negative) to negative (positive) direction under a large IDC. From here, onemay find that the modulation of the exchange bias in our text is totally different from the normal case onethinks, where the Heb becomes zero under a large enough IDC due to the pure heating effect. Therefore, webelieve that the above results show that our method can modulate in situ the linear field range and sensitivity,which has important significance in guiding the optimization of the performance parameters of magneroresistivesensors.