The magnetic and magneto-optical properties of PtCo thin films

Magneto-optic, magnetic and structural techniques were used to examine the properties of Pt/Co multilayers and the variation of the manufacturing conditions was found to greatly effect these properties Three conditions were required to produce multilayers with rectangular polar Kerr hysteresis loops with coercivities of 3.3kOe and polar Kerr rotations of 0.32 deg. These were the use of a thin platinum underlayer, the sputter etching of both the substrate and the underlayer and the sputter gas pressure used. The properties of these multilayers after heating in a variety of conditions were examined and it was found that the coercivity and polar Kerr loop shape could be altered by the use of the appropriate heating conditions. The coercivity of multilayers with the same nominal structure could be varied between 1.7 and 10.3kOe, although the nucleation field was never greater than 6.2kOe. The mechanism behind these coercivity changes is related to the oxidation of cobalt in the multilayer and is discussed in detail. The magnetic reversal mechanisms of a set of multilayers with a range of coercivities are also examined. The properties of stacked multilayers (i.e. one deposited on top of the other) were examined with a view towards direct overwrite applications. It was found that the use of a platinum spacer layer effected the exchange coupling between the two stacked multilayers. The variation of the Curie temperatures with individual multilayer structure is also reported. (author)SIGLEAvailable from British Library Document Supply Centre- DSC:DXN059141 / BLDSC - British Library Document Supply CentreGBUnited Kingdo