35 巻 (2011) 1 号 p. 1-6
Bit-shifts of recorded magnetization have been investigated using a magnetic force microscope (MFM) for a perpendicular recording medium when exposed to perpendicular magnetic fields at various sample temperatures (RT-200°C). The bit-shift is measured as a position difference of magnetization transition which is estimated from the differentiated MFM line intensity profile observed for a same pair bits before and after exposure to a magnetic field. It is shown that the critical magnetic field above which bit-shift starts to be observed decreases drastically while the bit-shift length increases with increasing the sample temperature. The variation of bit-transition-shift along the recorded track center as well as along the edge can be precisely measured by using the method.