The effect of an Al underlayer on the magnetic and microstructural properties of CoCr(Pt)Ta/Cr films deposited on glass substrates were investigated. The coercivity increased and the coercivity squareness decreased by introducing an Al underlayer. The cause of the coercivity increase is attributed to the the increase of in-plane c-axis orientation, the increase of magnetic isolation of Co-grains, and the refinement of Co-grains deposited on Cr/Al underlayers. The decrease of coercivity squarenesses seems to be caused by the increase of magnetic isolation. To examine the effects of magnetic isolation of Co-grains on the magnetic properties, the angular variations of coercivities of magnetic films were measured. The degree of magnetic isolation of Co-grains on Cr/Al is larger than that of Co-grains on Cr. The increase of magnetic isolation of Co-grains deposited on Cr/Al underlayers were attributed to the diffusion of Al atoms into grain boundaries of Co-films and the physical isolation of Co-grains.
The effect of AlN underlayers on the magnetic properties and the morphology changes of CoCrPtTa/Cr films were also studied. The AlN underlayers were fabricated by N2 reactive sputtering. The introduction of AlN underlayers also increased the coercivities of CoCrPtTa/Cr films and decreased the coercivity squarenesses. These magnetic property changes were caused by the physical isolation of Co-grains.
The tribological performance of CoCrTa/Cr/Al on glass substrate was evaluated by CSS test. The friction coefficient was low at the initial stage.
