IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Magnetic Recording Topical Conference Wednesday Sessions
       Session MR+AS+SE-WeA

Paper MR+AS+SE-WeA10
Thermal Stability of Granular Perpendicular Magnetic Islands Patterned using a Focused Ion Beam

Wednesday, October 31, 2001, 5:00 pm, Room 110

Session: Magnetic Recording: Heads & Media
Presenter: S. Anders, IBM Almaden Research Center
Authors: S. Anders, IBM Almaden Research Center
C.T. Rettner, IBM Almaden Research Center
M.E. Best, IBM Almaden Research Center
B.D. Terris, IBM Almaden Research Center
Correspondent: Click to Email
We have studied the thermal stability of patterned magnetic media islands as a function of island size. A focused ion beam (30 keV, Ga+) was used to pattern granular CoCrPt media to produce square arrays of islands of different periods, ranging from 70-750 nm. Islands with periods smaller than 130 nm appear as single magnetic domains in MFM images, while larger islands show multi-domain behavior. The samples were magnetized perpendicularly in a field of 20 kOe (far in excess of the ~3 kOe coercivity) to produce fully magnetized films. This fully magnetized state should have the highest decay rate, since the demagnetization field is maximized. Magnetic force microscopy images taken at various times after the magnetization show that the patterned structures have a considerably slower thermal decay rate than the unpatterned film. Small single-domain islands were seen to have the smallest decay rate of less than 0.25% per decade compared to one order of magnitude higher decay rates for the unpatterned media. This enhanced stability is analyzed in terms of increased demagnetization fields and increased switching volumes introduced by patterning.