Magnets for Hybrid Car Engines
In the area of permanent magnets, we are exploring the reversal mechanism of hard permanent magnets in order to improve their utility for alternative energy purposes. We strive to develop stronger permanent magnets with higher Curie temperatures and lower rare-earth content. We study the competition of domain wall propagation and nucleation in sintered and nanostructured rare earth magnets. We are analyzing hard-soft composite structures.
In the area of magnetic recording, we are collaborating with Kai Liu’s group, studying graded columnar media and nanopatterned media to achieve higher density, lower energy recording systems. Among others, we are focusing on HAMR and bit patterned media, and the study of the L10 phase of FePt.
Toyota supports our collaborative effort with T. Schrefl and M. Winklhofer. This is a comprehensive research project, in close interaction with several experimental groups. We use the following tools:
- the FEMME finite element LLG code for micromagnetics
- the OOMMF code for micromagnetics
- the FORC analysis in the mean field + local corrections framework
- analytic methods in one dimension
- elastic rubber band method for determining energy barriers.
In magnetic recording, we are collaborating with Kai Liu’s group, and use micromagnetic, FORC and analytic tools.
- 2016 Spin-wave renormalized Finite Element Magnetic modeling FORC Conference, New Orleans
- 2013 Quantitative FORC Analysis: Mean Field Theory and Local Cluster Corrections Part I Part II UC Davis, Davis CA
- 2010 The FORC.M2.alpha Method Magnetism and Magnetic Materials conference Atlanta, GA
- 2007 Extracting the Switching Field Distribution by the FORC Method Magnetism and Magnetic Materials conference, Baltimore, MD
- 2007 Optimizing Graded Media Magnetism and Magnetic Materials conference, Baltimore, MD
- 2020. S. Westmoreland, T. Ostler, R. Evans, R. Chantrell, C. Skelland, M. Yano, T. Shoji, A. Kato, M. Ito, M. Winklhofer, G.T. Zimanyi, J. Fischbacher, T. Schrefl, G. Hrkac. Atomistic study on the pressure dependence of the melting point of NdFe 12. AIP Advances, 10, 025130.
- 2019. T. Ostler, S. Westmoreland, R. Evans, R. Chantrell, C. Skelland, M. Yano, T. Shoji, A. Kato, M. Winklhofer, G.T. Zimanyi, J. Fischbacher, T. Schrefl, G. Hrkac. The Effect of Interstitial Nitrogen Addition on the Structural Properties of Supercells of NdFe 12-x Tix. IEEE Transactions on Magnetics, 55, 1.
- 2019. A. Grutter, P. Neves, G-J. Shu, Guo-Jiun; G.T. Zimanyi, D. Gilbert, B. Maranville, F-C. Chou, K. Krycka, N. Butch, S-X. Huang, J. Borchers. Precipitating ordered skyrmion lattices from helical spaghetti and granular powders. Physical Review Materials, 3, 014408.
- 2018. C. Skelland, T. Ostler, S. Westmoreland, R. Evans, R. Chantrell, M. Yano, T. Shoji, A. Manabe, A Kato, M. Ito, M. Winklhofer, G.T. Zimanyi, J. Fischbacher, T. Schrefl, G. Hrkac, Probability Distribution of Substituted Titanium in RT12 (R = Nd and Sm; T = Fe and Co) Structures. IEEE Transactions on Magnetics, 54, 2103405.
- 2018. S. Westmoreland, R. Evans, G. Hrkac, T. Schrefl, G.T. Zimanyi, M. Winklhofer, N. Sakuma, M. Yano, A. Kato, T. Shoji, A. Manabe, M. Ito, R. Chantrell. Multiscale model approaches to the design of advanced permanent magnets. Scripta Materialia, 148, 56.