Institut für Materialwissenschaft, Technische Universität Darmstadt, D-64287 Darmstadt, Germany
Abstract:
The insatiable desire of modern industry for high performance permanent magnets is expected to grow further, as new branches, e.g., electromobility, wind turbines and magnetic refrigeration, are about to come on stream [1]. Today’s high performance magnets contain light rare earth elements, such as neodymium and/or praseodymium, as well as a small amount of heavy rare earths, dysprosium and/or terbium. The latter in particular are in short supply, the current situation still being viewed as critical.
Achieving a very strong magnetic anisotropy in a 3d material is a difficult, but not an impossible task [2]. It is difficult because there is no general recipe for a strong anisotropy in a band magnet and the basic boundary conditions will be described in this paper. Several strategies can be pursued explore the feasibility of a rare earth free solid with outstanding intrinsic properties necessary for permanent magnet applications. One of them is to reexamine the less studied 3d compounds, somewhat neglected since the discovery of the Nd–Fe–B magnets 30 years ago. We give examples of our on-going research describing Mn-based systems, the LaCo5-x systems and (Fe,Co,X)2B systems [4,5] which involve multi-scale modelling and characterization as well as single crystal growth and field-assisted processing.
Achieving a very strong magnetic anisotropy in a 3d material is a difficult, but not an impossible task [2]. It is difficult because there is no general recipe for a strong anisotropy in a band magnet and the basic boundary conditions will be described in this paper. Several strategies can be pursued explore the feasibility of a rare earth free solid with outstanding intrinsic properties necessary for permanent magnet applications. One of them is to reexamine the less studied 3d compounds, somewhat neglected since the discovery of the Nd–Fe–B magnets 30 years ago. We give examples of our on-going research describing Mn-based systems, the LaCo5-x systems and (Fe,Co,X)2B systems [4,5] which involve multi-scale modelling and characterization as well as single crystal growth and field-assisted processing.
[1] O. Gutfleisch et al., Magnetic Materials and Devices for the 21st Century: Stronger, Lighter, and More Energy Efficient, Adv. Mat. 23 (2011) 821.
[2] M.D. Kuz´min et al., Towards high-performance permanent magnets without rare earths, J. Phys.: Condens. Matter 26 (2014) 064205.
[3] S. Ener, K. Skokov, D.Yu Karpenkov, M.D. Kuzmin, O. Gutfleisch, Magnet properties of Mn70Ga30 prepared by cold rolling and magnetic field annealing, JMMM 382 (2015) 265.
[4] Hong Jian, K.P. Skokov, M.D. Kuzmin, I. Radulov, O. Gutfleisch, Magnetic properties of (Fe,Co)2B alloys with easy-axis anisotropy, IEEE Trans. Magn. 50 (2014) 2104504.
[5] A. Edström, M. Werwinski, J. Rusz, O. Eriksson, K.P. Skokov, I.A. Radulov, S. Ener, M.D. Kuz’min, J. Hong, M. Fries, D. Yu. Karpenkov, O. Gutfleisch, P. Toson , J. Fidler, Effect of doping by 5d elements on magnetic properties of (Fe1−xCox)2B alloys, Phys. Rev. B, submitted.
[2] M.D. Kuz´min et al., Towards high-performance permanent magnets without rare earths, J. Phys.: Condens. Matter 26 (2014) 064205.
[3] S. Ener, K. Skokov, D.Yu Karpenkov, M.D. Kuzmin, O. Gutfleisch, Magnet properties of Mn70Ga30 prepared by cold rolling and magnetic field annealing, JMMM 382 (2015) 265.
[4] Hong Jian, K.P. Skokov, M.D. Kuzmin, I. Radulov, O. Gutfleisch, Magnetic properties of (Fe,Co)2B alloys with easy-axis anisotropy, IEEE Trans. Magn. 50 (2014) 2104504.
[5] A. Edström, M. Werwinski, J. Rusz, O. Eriksson, K.P. Skokov, I.A. Radulov, S. Ener, M.D. Kuz’min, J. Hong, M. Fries, D. Yu. Karpenkov, O. Gutfleisch, P. Toson , J. Fidler, Effect of doping by 5d elements on magnetic properties of (Fe1−xCox)2B alloys, Phys. Rev. B, submitted.