Patterned Bit Cell Arrangement and Broadening of Switching Field Distribution Caused by Magneto-Static Interactions

Patterned media technology is a promising approach for future high density magnetic data storage. The bit-to-bit spacing becomes smaller as recording density increases. As a result, the magneto-static field (H_d) from the surrounding bits becomes stronger, and contributes more to the broadening of the switching field distribution (SFD) of targeted bit. This paper reports the investigations between possible bit-cell arrangements and SFD broadening caused by the magneto-static field. The possible bit-cell arrangements are categorized into three groups-square arrangement, isosceles triangular arrangement, and equilateral triangular arrangement. The influences of manufacturing induced deviations, including bit-cell position offset and bit-cell size variation, over the H_d are also simulated. The results suggested that isosceles triangular arrangement can reduce the SFD broadening, without increasing the requirement on track positioning accuracy.