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Exchange coupled composite (ECC) media exhibits a lower switching field than conventional perpendicular media at the same level of thermal stability, and thus is able to achieve higher areal density. The inhomogeneity of ECC media is predicted to enhance the thermal attempt frequency: this increases both writability and adjacent track erasure (ATE). The adverse change in ATE is, however, countered by the angular dependence of the ECC media switching field. This angular dependence is further exploited with a head design featuring a larger pole width than track width and the introduction of notches in the down track direction. This reduces the effect of head skew and increases the write field. An optimized head is found to be consistent with terabit/[in.sup.2] recording. Index Terms--Exchange coupled composite (ECC) media, pole head, thermal fluctuation.

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. Index Terms--Exchange coupled composite media, perpendicular magnetic recording, thermal fluctuations.

Exchange-coupled composite (ECC) media consisting of hard and soft coupled regions has been predicted to exhibit attempt frequencies that are much larger than conventional perpendicular media due to the presence of two degrees of freedom. As a result, adjacent track erasure (ATE) and archivability are adversely affected, whereas writability is significantly enhanced due to thermal fluctuation assisted recording. Recording heads for ECC and perpendicular media, designed dimensionally for recording at 250 Gbits/[In.sup.2], are evaluated within this context. In comparison, recording on ECC media is shown to yield about a factor 2 advantage in areal density. Index Terms--Attempt frequency, exchange-coupled composite (ECC) media, perpendicular recording, thermal fluctuations.

A writer is designed for 10-nm-thick exchange coupled composite (ECC) media. At the air bearing surface (ABS), the writer is 60 nm x 60 nm. Down track notches, cross track flares, and side shields are employed. A recording density of 1.18 Tb/[in.sup.2] is achieved based on the write field profile. The bit aspect ratio (BAR) is estimated to be 8.9. Index Terms--Exchange coupled composite (ECC) media, perpendicular recording, perpendicular writer.

The fabrication of CoB/Pd multilayers for reducing the intergranular exchange and for inhibiting the grain growth at elevated temperature is discussed. An areal recording density of 10.92 Gb/in(super 2) at bit-error-rate (BER) of 10(super -6) with a potential of 30 Gb/in(super 2) is observed in the CoB/Pd multilayer perpendicular media.

The characteristics of perpendicular recording media with a soft underlayer are examined with the help of a readback model. The media signal to noise ratio (SNR) declines by about 4.7 dB due to cluster formation with areas equal to about three times the grain size.

Micromodeling is used for examining the remnant field of a single pole type (SPT) writer with both cross and down track flares. The studies have shown that this design has reduced the remnant field considerably and has produced both a high write field and a square shaped footprint.

A perpendicular recording head for an areal density of 1 Tbit per square using a self-consistent three-dimensional (3D) micromagnetic model is discussed. Finally simulations show that a high perpendicular H(sub k) reduces the flux spreading from the narrow tip, therefore it enhances the recording field.