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Tuning magnetic anisotropy in (001) oriented
L1₀ (Fe_1-xCu_x)₅₅Pt₄₅ films

Dustin A. Gilbert¹, presenter,
Liang-Wei Wang², Timothy J. Klemmer³, Jan-Ulrich Thiele³, Chih-Huang Lai², and Kai Liu¹,*
¹Physics Department, University of California, Davis, CA 95616 USA
²Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan
³Seagate Technology, Fremont, CA 94538 USA

Abstract

The development of high anisotropy magnetic materials that are compatible with industrial processing is critical in advancing magnetic recording, permanent magnet, and spintronic technologies. Specifically, high anisotropy materials are necessary to ensure long-term thermal stability in magnetic nanoelements, such as ultra-high density recording media and magnetic memory. A material of particular interest is L10 ordered FePt because of its large magneto-crystalline anisotropy, saturation magnetization, and chemical stability. A key limiting factor has been the high annealing temperature necessary to transform the as- deposited disordered face centered cubic (fcc) A1 phase into the ordered tetragonal L10 phase.

We have achieved (001) oriented L1₀ (Fe_1-xCu_x)₅₅Pt₄₅ thin films, with magnetic anisotropy up to 3.6×10⁷ erg/cm³, using atomic- scale multilayer sputtering and post annealing at 400 °C for 10 seconds, which is a much lower temperature annealing for a much shorter time compared to earlier studies. By fixing the Pt concentration, structure and magnetic properties are systematically tuned by the Cu addition. Increasing Cu content results in an increase in the tetragonal distortion of the L10 phase, significant changes to the film microstructure, and lowering of the saturation magnetization and anisotropy. The relatively convenient synthesis conditions, along with the tunable magnetic properties, make such materials highly desirable for future magnetic recording technologies.

This work has been supported by the NSF (DMR-1008791). Work at NTHU has been supported in part by Hsinchu Science Park of Republic of China under Grant No. 101A16.

Copy Of Presentation

Biography

Dustin A. Gilbert received his BS in Physics from the University of California, Santa Cruz in 2008, MS in Physics at the University of California, Davis in 2009, and is currently completing his Ph.D. at the same institute working with Prof. Kai Liu. He has previously conducted research at Seagate, Naval Postgraduate School in Monterey, and CUBIC Defense Applications in San Diego. He has published 10 refereed journal papers and received a variety of recognitions, including the 2012 IEEE Magnetics Society Summer School Participant, NSF Graduate Student Fellowship Program ‘honorable mention’ in 2010, and the US Department of Homeland Security CHSC fellowship in 2008. His research interests include magnetic materials, magnetic interactions, and hysteretic reversal behavior.

• Dustin A. Gilbert
• Physics Department, University of California, Davis, CA
• dagilbert [at] ucdavis [dot] edu