The impact of slider surface roughness on the touchdown-takeoff hysteresis phenomenon | |
| Author | Ramida Vithoonsaritsilp |
| Call Number | AIT Thesis no.ISE-12-40 |
| Subject(s) | Surface roughness Hysteresis Hard disks (Computer science) |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Microelectronics and Embedded Systems, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. ISE-12-40 |
| Abstract | Hard Disk Drives (HDD) are on e of the most complex data storage devices but are widely used. As the demand of higher areal density is increasing substantially, the spacing between the magnetic head and disk is targeted to be smaller than 5nm to attain better read/write capability. At such small clearance, considering the short range forces such as, van de Waal forces, meniscus forces, dynamic instability of the head - disk interface has become inevitable. Touchdown - Takeoff (TD - TO) Hysteresis is a well - known method to investigate the s tability of the head - media interface. Hysteresis is defined as the duration for which the head contacts the disk surface (TD) and subsequently recovers from contact (TO). Slider surface roughness is a key contributor to improve the TD - TO Hysteresis behavio r. Increasing the roughness is proposed to minimize the head instability due to intermolecular forces on the slider surfaces by shifting the mean - plane roughness in conjunction to reduced vibration, friction and stiction upon sliding contacts. This concept also aims to improve the recovery of the Air Bearing Surface (ABS) after a TD event. Despite many analytical models that have been developed over the last decade, existing experimental results lack supporting the proposed concept. In this study, three d ifferent roughnesses Al TiC sliders were produced (0.2nm, 0.6nm, and 1.0nm RMS) using the ion beam sputtering method. They were then assembled into magnetic heads and the heads were subsequently tested using a tribology spinstand to observe the TD - TO Hyster esis phenomenon at nominal and stressed conditions. The impact of ABS design on the TD - TO Hysteresis of textured sliders was also studied. Pitch Static Altitude (PSA) of the magnetic heads and percentage (%) Bonded - Lube Ratio (BLR) of the magnetic disks we re also varied to stress the head - disk interface in order to assess the benefit of textured sliders. No significant impact was observed on TD events regardless of surface roughness at both nominal and stressed test conditions. However, TO events of these three different textured sliders were clearly affected by ABS design, PSA, and %BLR. The roughest text ured sliders (1.0nm) showed a significant improvement in TD - TO Hysteresis phenomenon over both smoother 0.2nm and 0.6nm textured sliders. |
| Year | 2012 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. ISE-12-40 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Industrial Systems Engineering (DISE) |
| Academic Program/FoS | Industrial Systems Engineering (ISE) |
| Chairperson(s) | Dutta, Joydeep |
| Examination Committee(s) | Hornyak, Louis;Best, George Lawrence |
| Scholarship Donor(s) | Asian Institute of Technology Fellowship;Western Digital-NECTEC, Thailand |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2012 |