Direct observation of magnetic bit transition and physical grain boundary in perpendicular recording media

The correlation between magnetic bit transition line and physical grain boundary in a multilayer perpendicular recording medium is examined by combined magnetic force and electrostatic force microscopy. Reducing the scan height results in stronger electrostatic interaction between the tip and the sample disk. This electrostatic interaction causes the topographical information to be superimposed onto the magnetic force image and allows simultaneous imaging of the columnar grains and the magnetic bits. It is found that the magnetic transition follows the physical grain boundaries with high accuracy. The correlation of both is quantified by image processing and a correlation coefficient of 0.92 has been determined. (C) 2003 American Institute of Physics.