Thermal stability of longitudinal media for <20 Gbits/in/sup 2/ recording

Abstract

The thermal stability of a CoCrPtB-based media for over 20 Gbit/in 2 recording is investigated by magnetometry and spin stand methods. Recent quaternary and 5-element alloys for longitudinal magnetic recording media show significantly reduced grain sizes compared to Co-Cr-Pt-Ta alloys for the same underlayer structure. Cr segregation was also enhanced and the Cr-rich regions between grains were wider than those of CoCrPtTa media. These resulted in significant gains in necessary for high density and high data rate recording and also in the degradation of magnetic thermal stability. Although higher densities can be achieved by decreasing the bit aspect ratio, side erasure problems due to flux leakage from narrow write heads are worsened.Index Terms-Thermal stability, high density longitudinal recording, side erasure, overwrite, CoCrPtB.

Synthetic ferrimagnetic media

“…For the latter case, the media was initially demagnetized by application of decreasing positive and negative fields. DC remanence curves are similar for SFM and conventional media [6], [7], [9], [11]. Therefore, the recording process is roughly as follows: the head field aligns the magnetization of the portion directly under the head gap of layers and in one direction and as the write head is moved away, the magnetization of layer is reversed due to .…”

“…All measurements were made at room temperature. As a guide to estimate decay rates at 65 C, measurements of the remanence magnetization decay in the presence of a reversing field were made using a SQUID magnetometer at room temperature and at 65 C. The reversing field used at 65 C was lower to account for the decrease in [11]. There was approximately a two-fold increase in decay at elevated temperatures compared to that at room temperature.…”

“…Thermal stability measurements were made on a Kyodo-Denshi spinstand with a Guzik controller and an analog HP8655 spectrum analyzer in zero span [11]. The head is a commercial head being used for a 7.3 GB/platter 10K rpm enterprise drive.…”

Electrochemical Synthesis of Metal Alloys for Magnetic Recording Systems

“…À2 [6], and demonstration of 170 Gbits Á in. For a perpendicular medium, the sputter deposition of CoCr alloy film, which was first reported by Iwasaki and Ouchi [10], and the control of grain orientation, grain size, and magnetic properties of film also have contributed to the progress in areal density [9][10][11][12]. However, there has been an apparent slowdown in this increase of density.…”