Large energy product enhancement in perpendicularly coupled MnBi/CoFe magnetic bilayers

Authors

• T. R. Gao, University of Maryland at College Park
• L. Fang, University of Maryland at College Park
• S. Fackler, University of Maryland at College Park
• S. Maruyama, University of Maryland at College Park
• X. H. Zhang, University of Maryland at College Park
• L. L. Wang, U.S. Department of Energy
• T. Rana, Univeristy of Nebraka - Lincoln
• P. Manchanda, University of Nebraska-Lincoln
• A. Kashyap, LNM Institute of Information Technology
• K. Janicka, U.S. Department of Energy
• A. L. Wysocki, U.S. Department of Energy
• A. T. N’Diaye, Lawrence Berkeley National Laboratory
• E. Arenholz, Lawrence Berkeley National Laboratory
• J. A. Borchers, National Institute of Standards and Technology
• B. J. Kirby, National Institute of Standards and Technology
• B. B. Maranville, National Institute of Standards and Technology
• K. W. Sun, U.S. Department of Energy
• M. J. Kramer, U.S. Department of Energy
• Vladimir P. Antropov, Iowa State UniversityFollow
• D. D. Johnson, U.S. Department of Energy
• Ralph Skomski, University of Nebraska-LincolnFollow
• J. Cui, Pacific Northwest National Laboratory
• I. Takeuchi, University of Maryland at College Park

Document Type

Article

Date of this Version

2016

Citation

PHYSICAL REVIEW B 94, 060411(R) (2016)

Comments

©2016 American Physical Society

Abstract

We demonstrate substantial enhancement in the energy product of MnBi-based magnets by forming robust ferromagnetic exchange coupling between a MnBi layer and a thin CoFe layer in a unique perpendicular coupling configuration, which provides increased resistance to magnetization reversal. The measured nominal energy product of 172 kJ/m³ at room temperature is the largest value experimentally attained for permanent magnets free of expensive raw materials. Our finding shows that exchange-coupled MnBi/CoFe magnets are a viable option for pursuing rare-earth-free magnets with energy products approaching those containing rare-earth elements.