GOALI: Sub Resolution Magnetic Recording at 10 Terrabit/inch2
Intellectual Merit: Research employing write and read heads operating below resolution is proposed. The original user data will be reconstructed using two dimensional (cross-track and down-track directions) signal processing as proposed by Roger Wood and coworkers. Numerous channel bits will be employed, e.g., 40 Terrabits/inch2 of channel bits to represent 10 Terabits/inch2 of user data. The proposed research includes searching for a workable arrangement of read sensors and exploring write head designs suitable for this very high density. The use of dual magnetoresistive sense heads with lateral extent considerably exceeding the track width is proposed. They will be arranged in a linear array tilted at a skew angle to the track, thus allowing each head to be sensitive to a different set of read tracks and the signal from each track to be extracted. A variety of approaches for the write head will be examined using two micromagnetic codes. A particularly interesting idea is the use of an antiferromagnetically coupled secondary pole to maximize gradient. The ultimate goal is to test this idea of two dimensional magnetic recording using magnetic heads and media that are designed to optimize its performance.
The proposed research represents a collaborative effort between University of Minnesota Professor Randall Victora (magnetics), and Seagate engineer Fatih Erden (signal processing). The plan involves multiple iterations, each including an encoded signal (provided by Dr. Erden) written micromagnetically on composite media using a novel write head architecture. The two dimensional signal will then be obtained by the read head array and the waveforms will be sent to Seagate for decoding. The iteration will end with feedback from Seagate about the performance and causes of failure. This will lead to a new magnetic design and/or signal processing algorithm, and a new iteration.
Broader Impact: The proposed research will impact three important constituencies: undergraduate students who want to learn about research, graduate students who are beginning their research careers, and fellow researchers with particular emphasis towards industry. Graduate students will benefit from extensive contact with industry including joint optimization of magnetic and signal processing constraints with Seagate and through industrial internships. The interdisciplinary environment of the Center for Micromagnetics and Information Technology (MINT) will also expose them to students from other disciplines and a large number of industrial visitors, particularly at the Annual Review. Undergraduates will be included within the proposed research through the Research Experience for Undergraduates program at the University of Minnesota and, for exceptional students, Senior Honors Theses. In an effort to reach industries beyond Seagate, a visit to multiple U.S. based recording companies is proposed for each year. This, together with the Annual MINT Review will allow industrial researchers an opportunity to discuss detailed research results with the investigators.
