7-10-2012 Multilevel-3 D Bit Patterned Magnetic Media with 8 Signal Levels

This letter presents an experimental study that shows that a 3 physical dimension may be used to further increase information packing density in magnetic storage devices. We demonstrate the feasibility of at least quadrupling the magnetic states of magnetic-based data storage devices by recording and reading information from nanopillars with three magnetically-decoupled layers. Magneto-optical Kerr effect microscopy and magnetic force microscopy analysis show that both continuous (thin film) and patterned triple-stack magnetic media can generate eight magnetically-stable states. This is in comparison to only two states in conventional magnetic recording. Our work further reveals that ferromagnetic interaction between magnetic layers can be reduced by combining Co/Pt and Co/Pd multilayers media. Finally, we are showing for the first time an MFM image of multilevel-3D bit patterned media with 8 discrete signal levels. Citation: Amos N, Butler J, Lee B, Shachar MH, Hu B, et al. (2012) Multilevel-3D Bit Patterned Magnetic Media with 8 Signal Levels Per Nanocolumn. PLoS ONE 7(7): e40134. doi:10.1371/journal.pone.0040134 Editor: Jie Zheng, University of Akron, United States of America Received April 2, 2012; Accepted June 1, 2012; Published July 10, 2012 Copyright: 2012 Amos et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was supported by the National Science Foundation (NSF) under contracts 005084-002 and 0824019 and DARPA/Defense Microelectronics Activity (DMEA) under agreement number H94003-09-2-0904. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have read the journal’s policy and have the following conflicts: Patent Application on Three Dimensional Magnetic Recording: Application number: 12/506,042; Publication number: US 2010/0149676 A1; Filing date: Jul 20, 2009. This does not alter the authors’ adherence to all the PLoS ONE policies on sharing data and materials. * E-mail: Nissim.Amos@ee.ucr.edu