Interlayer coupling in a trilayer junction having bismuth as spacer layer

Abstract

A trilayer system (CoFe∕Bi∕Co) with bismuth as a spacer layer was synthesized using dc sputtering at room temperature. Magnetization studies show that the interlayer coupling between two ferromagnetic electrodes oscillates with the thickness of Bi spacer layer at room temperature, as seen in most metallic spacers, but it has a much longer period, which is estimated to be 180to200Å. Furthermore, the range of interlayer coupling between two ferromagnetic layers separated by Bi spacer can be extended up to 500Å. As the measuring temperature is reduced, the strength of interlayer coupling increases and varies with Bi thickness in a similar way, but the oscillation amplitude decreases.