THE MICROSTRUCTURE AND MAGNETIC-PROPERTIES OF COBALT-RICH CO-PT ALLOYTHIN-FILMS GROWN USING ION-BEAM-ASSISTED DEPOSITION

This study investigates the magnetic and microstructural properties of Co1-xPtx thin films (x = 0.20 and 0.25) grown by ion-beam-assisted ma gnetron-sputtering deposition with ion beam energies up to 500 eV. The hysteresis behaviour, particularly the coercivity, changes dramatical ly with the ion-beam energy (IBE). The in-plane coercivity rises sharp ly up to IBE = 250 eV and drops thereafter. The c axis leaves the film plane with increasing IBE and eventually aligns normal to the film pl ane for films deposited at 500 eV. Detailed microstructural investigat ions reveal that cc-bombarding the film during growth leads to the evo lution of a faulted microstructure. High-resolution TEM results show t hat the defect structure consists of FCC lamellae slipped along the cl ose-packed (111) planes. The faulted regions may provide pinning sites for the wall motion during magnetization reversal, thus leading to an enhancement of the coercivity.