EXCHANGE COUPLING IN NIO NI DOUBLE-LAYER FILMS/

NiO/Ni double layer films were prepared by partial oxidation of Ni fil ms deposited on MgO(100) substrates by a vacuum evaporation method, an d the exchange coupling field H-ex and the easy coercive force H-ce in the films were studied in relation to the substrate temperature T-s a nd the oxidation temperature. As a result, it is found that (1) Ni fil ms deposited at low T-s (100 degrees C) are easily oxidized at low tem peratures (similar to 450 degrees C), compared with those deposited at higher T, (200 degrees C or 300 degrees C), (2) H-ex and H-ce in NiO/ Ni double layer films prepared at low temperatures are large compared with those in films prepared at high temperatures. The reasons for the increase of H-ex and H-ce in NiO/Ni films prepared at low temperature s are discussed.