head-disk interface wear reduction analysis using helium environment and tip-enhanced raman spectroscopy

Department: Mechanical & Aerospace Engineering
Faculty Advisor(s): Frank E. Talke

Primary Student
Name: Tan Duy Trinh
Email: tdtrinh@ucsd.edu
Phone: 850-716-4998
Grad Year: 2019

Student Collaborators
Benjamin Suen, bsuen@ucsd.edu | Andreas Rosenkranz, arosenkranz@ucsd.edu

The tribological characteristics of the head-disk interface are investigated during load-unload for air and helium-filled drives as a function of the pitch static angle and the roll static angle between slider and disk. A custom-made experimental tester inside a sealed environmental chamber was used to determine the regions of "safe" pitch static angle and "safe" roll static angle in air and helium environment during the load-unload process. The presence of head-disk contacts during load-unload were evaluated by measuring the acoustic emission signal and the decrease in rotational speed of the spindle. Scanning electron microscopy and optical surface analysis were used to investigate wear of the slider and the redistribution of lubricant on the disk surface after 10,000 load-unload cycles. The results indicate that the tribological performance of the head-disk interface are improved in helium environment compared to air environment. Heat assisted magnetic recording (HAMR) is a technology that can greatly increase the storage density in hard disk drives. HAMR writes bits of data by heating a nanoscale spot on magnetic recording media to approximately its curie temperature, applying a magnetic field, and then allowing the media to cool. The heating is accomplished with a laser and a near-field transducer. This recording process involves extreme temperatures and electromagnetic flux, which causes the degradation of lubricants and anti-wear coatings in the HAMR drive. We propose using tip-enhanced Raman spectroscopy (TERS) in order to measure the degradation and maximum temperature of the carbon anti-wear coatings in the HAMR drive. Through the analysis of the Raman spectra gathered from TERS, one can quantify chemical changes such as graphitization in the carbon coatings and correlate changes in peak positions and widths to changes in mechanical properties of the coatings. Furthermore, one may also be able to design near-field probes that may be able to generate HAMR-like radiation conditions in order to simultaneous simulate HAMR-like conditions and measure damage caused by the radiation.

Industry Application Area(s)
Civil/Structural Engineering | Materials | Semiconductor

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