Propagation of Exchange Bias in CoFe/FeMn/CoFe Trilayers

摘要

CoFe/FeMn, FeMn/CoFe bilayers and CoFe/FeMn/CoFe trilayers were grown inmagnetic field and at room temperature. The exchange bias field $H_{eb}$depends strongly on the order of depositions and is much higher at CoFe/FeMnthan at FeMn/CoFe interfaces. By combining the two bilayer structures intosymmetric CoFe/FeMn($t_\mathrm{FeMn}$)/CoFe trilayers, $H_{eb}^t$ and$H_{eb}^b$ of the top and bottom CoFe layers, respectively, are both enhanced.Reducing $t_\mathrm{FeMn}$ of the trilayers also results in enhancements ofboth $H_{eb}^b$ and $H_{eb}^t$. These results evidence the propagation ofexchange bias between the two CoFe/FeMn and FeMn/CoFe interfaces mediated bythe FeMn antiferromagnetic order.