EFFECTS OF FILM THICKNESS ON THE STRUCTURAL AND MAGNETIC-PROPERTIES OF COCRTA CO3O4/PT PERPENDICULAR THIN-FILM MEDIA/

This paper reports the effects of film thickness of room temperature R F sputtered trilayer CoCrTa/Co3O4/Pt films on the structural and perpe ndicular magnetic properties of CoCrTa magnetic layer. Using a 100 Ang strom Pt film with a weak (111) texture as the buffer layer improves t he nucleation and initial growth of the (111) oriented Co3O4 Seed laye r, which in turn induces a significantly strong (00.2) texture in CoCr Ta films. If the Pt is too thin, there are not enough (111) oriented s ites created for the nucleation of Co3O4 If the Pt is too thick, the l arge grain size with significant size variation in the magnetic layer (originating from the thick buffer layer) leads to poor perpendicular magnetic properties. A 50 Angstrom Co3O4 Seed layer sputtered on 100 A ngstrom Pt is most effective in promoting a strong (00.2) texture in C oCrTa films by providing (111) oriented sites for (00.2) growth of CoC rTa without creating significant lattice mismatch. For CoCrTa films sp uttered on this composite underlayer, the in-plane coercivity is not s ensitive to the film thickness whereas the perpendicular coercivity is . The maximum H-c perpendicular to (perpendicular coercivity) similar to 1650 Oe with an S-parallel to (in-plane remanant squareness) simila r to 13% is obtained when the film thickness is similar to 2000 Angstr om. The effect of the size of domain clusters on perpendicular coerciv ity H-c perpendicular to has also been studied by magnetic force micro scopy. (C) 1997 American Institute of Physics.