Patent ID: 9019646
Filing Date: 2015-04-28
Classification: G11B

Abstract:
1. An apparatus comprising: a write coil configured to apply a magnetic field to write data on a portion of a heat-assisted magnetic recording medium in response to an energizing current; an energy source configured to heat the portion of the medium being magnetized by the write coil; and wherein a preheat energizing current is applied to the write coil during an interval before writing the data to the portion of the medium, the energy source being de-energized during the interval, wherein the preheat energizing current applies the magnetic field to the medium, the magnetic field being sufficient to write to the medium when heated by the energy source but not causing other data to be written to the medium due to the energy source being de-energized, the preheat energizing current bringing at least one of the write coil and driver circuitry into thermal equilibrium prior to writing the data to the portion.