John W. Dykes

HAMR Drive Performance and Integration Challenges

The commercialization of heat-assisted magnetic recording (HAMR) presents some significant technical challenges that need to be resolved before the widespread adoption of the technology can begin. In this paper, we present some HAMR data from prototype drives and discuss some of the challenges related to protrusion management, recording performance optimization, and drive power requirements within the drive.

HAMR Performance and Integration Challenges

Heat-assisted magnetic recording (HAMR) is a fast evolving technology, and has been established as the next enabler of higher areal density in magnetic recording. After achieving high areal density capability, HAMR drive integration was recently demonstrated. In this paper, we discuss some of the recent learning from component performance and drive integration. We identify a key challenge in HAMR integration: erasure due to thermal background heating. The background heating was introduced to improve near-field transducer reliability and reduce laser power requirement. We present experimental and modeling data on the impact of thermal background, both in the cross-track (adjacent-track erasure) and down-track (self-erasure) dimensions.

Recording Performance of a Pulsed HAMR Architecture

In most heat-assisted magnetic recording (HAMR) systems, the laser is ON and kept constant during the entire sector. In this architecture, the transitions are defined whenever the magnetic writer changes polarity. In a pulsed HAMR system, the laser pulses once per bit. In this architecture, the transition is defined by the rising edge of the first laser pulse after a magnetic writer current transition. In this paper, we compare the bit error rate (BER) and areal density capability (ADC) of both continuous wave (CW) HAMR and pulsed HAMR. For our testing conditions, we find that there is no penalty for using a pulsed HAMR system over a CW HAMR system in terms of BER and ADC capability.

Characterization of HAMR using pulsed laser light

Pulsed Heat Assisted Magnetic Recording (HAMR) is being developed to improve HAMR reliability. In conventional HAMR systems the laser is on and at a fixed power during the writing of the entire sector. In a pulsed HAMR implementation, the laser is turned on and off during the bit cell. For example, for a 50% duty cycle, the laser is on for half the bit cell and off for the remainder of the bit cell. Unlike traditional HAMR where the transitions are formed when the magnetic writer switches, in a pulsed implementation the transitions are formed during the pulsing of the laser. In this paper we show spin stand and drive recording performance of pulsed HAMR systems and compare the outcome to conventional recording. In particular, we show the importance and sensitivity of having proper alignment between the phase of the optical and magnetic signals and their effect on bit error rate (BER).