STUDIES OF DEPOSITION ORDER ANOMALY OF EXCHANGE COUPLING IN BILAYERS AND TRILAYERS OF NIFE AND COO

The temperature dependence of the exchange field and coercivity and th e effect of deposition order have been studied in a series of bilayer (NiFe/CoO and CoO/NiFe) and trilayer (NiFe/CoO/NiFe) films. A profound difference in the exchange field temperature behavior was observed in samples with NiFe deposited on top of CoO compared to samples with Co O deposited on top of NiFe. When CoO is on top of NiFe, the exchange f ield follows a linear temperature dependence, while for samples with N iFe on top of CoO, the exchange field has a plateau followed by a rapi d decrease. These distinct temperature dependences are reproduced in t he NiFe/CoO/NiFe trilayer which contains both geometries. Transmission electron microscopy has been employed to study the interface between the NiFe and CoO layers. (C) 1997 American Institute of Physics.