1. Department
of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611-6400, United States
2. Department
of Electrical and Computer Engineering, University of Florida, Gainesville, Florida 32611-6200, United States
3. Department
of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16801-7003, United States
4. San Jose Research
Center, HGST, a Western Digital Company, San
Jose, California 95119, United States