Exchange coupled composite (ECC) media has been shown to possess several major advantages relative to conventional perpendicular media, including a reduction in the switching field of approximately a factor two for the same thermal stability and greater insensitivity to easy axis distribution. In this paper, full magnetostatic interactions are included: this allows comparison between the behavior of multi-grain thin films and that of isolated grains as presented earlier. Significant results include hysteresis loops for thin films under various conditions including inadequate and excessive intra granular exchange between the hard and soft materials. An important distinction is made between the coercivity and remnant coercivity as a function of angle between applied field and easy axis. A perpendicular magnetic recording head is used to compare the shape of effective fields for ECC and conventional perpendicular media. Written transitions in the ECC media appear to be similar to those written in perpendicular media at comparable densities.
Bibliographical noteFunding Information:
This work was supported in part by the National Science Foundation under Grant ECS-0300209 and in part by the INSIC EHDR program. The authors would like to thank the Minnesota Super Computing Institute for computing time.
- Exchange coupled composite media
- Perpendicular magnetic recording
- Thermal fluctuations