On the exchange biasing through a nonmagnetic spacer layer

We present results on the magnetic coupling between a ferromagnetic (F) thi n film and an antiferromagnetic (AF) thin film through a nonmagnetic metall ic spacer (S) layer. Multilayered structures have been grown on silicon sub strates using dc magnetron sputtering. We have studied the structure AF/S/F for different materials. AF is Ir22Mn78, F is Fe16Co16, and the spacer S i s Al, Ag, Au, Si, Pd, Ru, and Ti. In most cases, both the exchange-bias and the coercive fields decrease exponentially with the spacer thickness with a decay length of a few angstroms, depending slightly on the material. Simi lar decay lengths are observed for the reversed structure F/S/AF. In some s pecific cases, we observe a nonmonotonic variation of the exchange-bias fie ld with the spacer thickness. For example, the exchange-bias field increase s when a thin Ag layer is inserted between the F film and an AF film grown at high sputter pressure. (C) 2000 American Institute of Physics. [S0021-89 79(00)59508-5].