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Al2O3 films made with atomic layer deposition (ALD) have been developed for use as isolation layers in CPP tunneling magnetoresistive readers. A low-temperature deposition process was developed to permit integration with a self-aligned patterning scheme. The resulting films show excellent thickness uniformity (<2% within-wafer), leakage current density (Jleak < 1 x 10-8 A/cm²) and breakdown properties (Fbd > 9 MV/cm). TEMs of sub-100 nm TMR readers fabricated using these processes show > 95% conformality on junction sidewalls, indicating nonselective growth of ALD Al2O3 on the various stack and bottom shield surfaces. Permanent magnets with well-controlled junction grain structure and coercivities in excess of 2500 Oe have been deposited with existing processes. FEM modeling shows the effective stabilizing field from the magnets at the junction edge scales inversely with ALD layer thickness, in agreement with device-level free layer stability metrics showing improvements at lower ALD thicknesses. As the conformal ALD layer thickness is easily tuned, this technology provides flexibility in trading off reader amplitude and stability that should support scaling of the abutted TMR design out to 1 Tb/in² and beyond. [ABSTRACT FROM AUTHOR]

Deals with a strategy for high density perpendicular magnetic recording with a soft underlayer. Permeability of the recording layer; Discussion of exchange interaction between media; Description of the novel head architecture for high density perpendicular magnetic recording.

Perpendicular recording applications use a soft magnetic underlayer (SUL) in the media to enhance the writer field and control its angle. In this paper, a micromagnetic/FEM model (MagPar) was used to investigate the physics of the write process while a nonlinear magnetoelectrical model (Klaassen) helped identify the value of the damping constant under a particular MagPar mesh. The field strength and direction produces a domain under the writer pole in areas where the field opposes the SUL magnetization direction. These areas are located over the next tracks (right or left). This temporary domain changes the response of the SUL by affecting the flux path and increasing the return pole field near the domain. Since the return poles are very large and behave quite linearly, fields in some areas near the return pole edge are bigger due to large writer currents with overshoot and little or no damping from saturated regions. The return pole fields could be large enough to degrade transitions in adjacent tracks particularly when they are applied multiple times to those tracks. The erasure location changes with current polarity and SUL magnetization direction. [ABSTRACT FROM AUTHOR]

Adjacent track erasure in longitudinal recording was studied using a micromagnetic model. The gap and fringe fields of two heads designed to work for 100 kTPI were used to write and erase a 31-bit pseudorandom sequence (PRS) in the main track. Comparisons on recording performance were made based on the calculated magnetization profile and the equalized PRS read back signal. It was shown that, for the case of a 3800-Oe fringe field, the quality of the transitions degraded drastically when the transitions were exposed to the fringe field more than 1000 times. On the other hand, a 2000-Oe fringe field left unaffected transitions even when the transitions were exposed to the field more than 100 000 times. [ABSTRACT FROM AUTHOR]

The life time of stored data depends on the storage density as well as the physical properties and microstructure of the media. Perpendicular media for ultra-high density recording needs to have high anisotropy to withstand thermal instabilities over long time. In this study, we used a micromagnetic model based on a scaling method to numerically calculate the percentage of magnetic decay caused by thermal fluctuations after ten years. Realistic grain configurations for 1 Tbit/in² and 125 Gbit/in² recording were used to seek the critical grain magnetization and anisotropy field of magnetic media that are thermally stable for ten years. For less than 10% decay, an H[subK] of 20 kOe and M[supgrain][subS] of 600 emu/cm³ is required. Alternatively, H[subK] can be reduced to 16 kOe if M[supgrain][subS] is 800 emu/cm³. [ABSTRACT FROM AUTHOR]