| Author | Damrongsak Tongsomporn |
| Call Number | AIT Diss. no.ME-08-01 |
| Subject(s) | Magnetic recorders and recording Heads
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| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering in Microelectronics, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. ME-08-01 |
| Abstract | In ultrahigh recording density, the track width and bit length must be decreased for satisfying the required density. To achieve a shorter bit length, it requires having narrower bit transitions. To achieve a sharp bit transition, a recording system needs a higher write- field gradient at the trailing edge of main pole. The flying height reduction shows a strong capability to achieve this requirement. However, at a very low head-media clearance, the variation of flying height for a few nanometers has an influential effect to the recording performance. Therefore, it needs an adaptive flying-height (AFH) control to compensate the variations and optimize the performance of the recording system. This AFH control is achieved by thermal head protrusion using a heating element near the read/write element.
In this dissertation, the study emphasizes on examining the head-protrusion sensitivity of magnetic and electrical performance of perpendicular recording head and media using a spin-stand tester. The dependence of writability and readability on head protrusion is examined by measuring head-media clearance sensitivity of the parametric parameters during writing, reading, and read-write combination. The head-protrusion dependence of track width and bit length, which presents an areal density capability, is examined. The effect of head protrusion on write-saturation performance is also investigated.
The second part of the dissertation focuses on the effect of the temperature rise from the AFH heater on head functionality and reliability. The high temperature rise inside the slider head has a potential to degrade the magnetic properties of head materials of the read/write elements. This study examines and analyzes the effect of thermal stress and head protrusion from the AFH heater on the readability of TMR sensors using a quasi- static tester. The temperature dependence of TMR resistance and TMR ratio is studied. The effect of temperature rise and head protrusion on the sensor linearity and TMR noise is studied. The mechanism of head instability will be addressed to provide suggestions and recommendations for head instability improvement. In addition, this dissertation examines the impact of head instability, when turning on AFH capability, on the drive performance and head instability signatures using a drive failure analysis tool. The instability signatures will be confirmed by a quasi-static measurement to address the mechanism.
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| Year | 2008 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. ME-08-01 |
| Type | Dissertation |
| School | School of Engineering and Technology (SET) |
| Department | Department of Industrial Systems Engineering (DISE) |
| Academic Program/FoS | Microelectronics (ME) |
| Chairperson(s) | Afzulpurkar, Nitin V.; |
| Examination Committee(s) | Lertsak Lekawat;Manukid Parnichkun;Bargmann, Brent;Apirat Siritaratiwat
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| Scholarship Donor(s) | RTG Fellowship,; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2008 |