Optical forces in heat-assisted magnetic recording head-disk interface

Area of Science:

• Physics
• Materials Science
• Nanotechnology

Background:

• Heat-Assisted Magnetic Recording (HAMR) faces challenges with contaminant buildup, known as smear, on the near-field transducer.
• Understanding smear formation is crucial for improving HAMR reliability and performance.

Purpose of the Study:

• To investigate the role of optical forces, specifically those from electric field gradients, in the formation of smear in HAMR.
• To compare optical forces with other forces like air drag and thermophoresis at the head-disk interface.

Main Methods:

• Theoretical approximations were used to model and compare forces acting on smear nanoparticles.
• Simulations were conducted to evaluate the force field's sensitivity to various parameters.
• Analysis focused on two distinct smear nanoparticle shapes.

Main Results:

• Optical forces originating from electric field gradients are a significant factor in smear formation.
• Smear nanoparticle properties such as refractive index, shape, and volume critically affect optical force magnitude.
• Interface conditions, including spacing and the presence of other contaminants, also influence the optical force.

Conclusions:

• Optical forces play a key role in the accumulation of smear on HAMR near-field transducers.
• Controlling nanoparticle properties and interface conditions can mitigate optical force-induced smear.
• This research provides insights for designing more robust HAMR systems by addressing contaminant buildup.