Near Field Heat Assisted Magnetic Recording with a Planar Solid Immersion Lens

Abstract

In this paper we present experimental heat assisted magnetic recording results using a planar solid immersion mirror (PSIM) fabricated on an Al2O3–TiC slider. The heads were flown at a velocity of 14 m/s, 20–25 nm above a Co/Pt multilayer medium which was deposited on a 60 mm glass disk. It was found that the track width and carrier-to-noise-ratio (CNR) increased with the applied magnetic field. Recording experiments were also performed with PSIMs terminated with 125 µm apertures. This led to narrower tracks and smaller CNR values for the same applied fields compared to recording with a PSIM only.

Thermal Modeling of Optical Power Absorption in Moving Multilayer Thin Films

“…Douglas and Gunn [7] developed an ADI algorithm for the CN equation that maintains its unconditional stability and numerical accuracy but greatly reduces the computation time. In their technique Eq.…”

“…HAMR has been proposed for data storage densities of 1 Tb/in 2 or greater [7,8]. At these storage densities the optical spot size must be ~50 nm or smaller and the spacing between the recording head and the recording medium must be as small as possible, typically 5 nm, for adequate resolution of the bits in the readback signal.…”

“…Magnetic hard discs may also incorporate a hybrid optical/magnetic technology called "heat assisted magnetic recording" (HAMR) using near field optics to transfer the optical energy into the recording medium in a highly localized spot smaller than the total thickness of the film stack [7,8]. In such a case, the lateral heat flow can become as important as the perpendicular heat flow and thermal boundary conditions must be carefully applied.…”

Comatic Aberration in a Solid Immersion Mirror

“…In the devices measured here, ray optics is not a valid approximation and is considered for comparison only. Solid immersion mirrors of the design described in [1], [3] and illustrated in figure 1 were fabricated on air bearing sliders with the mirror's focus at the bearing surface as shown in figure 2. A beam of incident light is coupled into a thin film waveguide with a grating coupler.…”

Planar elliptical solid immersion lens based on a Cartesian oval

“…8 For emerging technologies, such as heat assisted magnetic recording (HAMR), it is necessary to create a small excitation focal volume with high power throughput using a compact device, which can be fabricated using standard lithography techniques. 9 Solid immersion lenses (SIL) give the possibility to achieve sub-wavelength focal spots while retaining high transmission. An SIL is in general a 3D hemisphere made from a high refractive index material which is placed close to the focal plane of a high NA objective.…”