No abstract

In recent years, the stability of recorded data against thermal decay has become an important criterion for judging the performance of magnetic recording systems. Continued growth of storage densities in the presence of thermally activated behaviour, often called the `superparamagnetic effect', requires new innovations in the recording system in general, and the recording media, in particular. This paper reviews some of the recent advances in recording media (e.g. oriented and antiferromagnetically coupled media) that have helped magnetic recording to maintain the areal density growth rate. However, more innovations and novel architectures are needed for the solutions of tomorrow. Among the more promising media approaches, which are discussed in this paper, are perpendicular, patterned and self-assembled nanoparticle media. Additionally, thermally assisted recording is also reviewed as it combines good writeability with high thermal stability.

No abstract

Direct measurements of heat capacity from 80 to 540 K of antiferromagnetic superlattices of NiO (high Néel temperature T N), CoO (low T N), and MgO (nonmagnetic) are used to study the effect of exchange coupling and layer thickness on magnetic ordering. NiO͞CoO superlattices with thin layers show a single heat capacity peak similar to a Ni 0.5 Co 0.5 O alloy; with increasing layer thickness, the peak splits into two maxima. Finite size effects are seen in uncoupled NiO and CoO. Observed shifts in T N show the importance of correlation lengths and spin fluctuations in the ordering.

No abstract