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New principle of magnetic recording

X. Marti1,2,3, I. Fina4,5, C. Frontera4, Jian Liu6, P. Wadley3,7, Q. He8, R.J. Paull1, J.D. Clarkson1, J. Kudrnovsky9, I. Turek2,10, J. Kunes3, D. Yi6, J.-H. Chu6, C.T. Nelson11, L. You12, E. Arenholz8, S. Salahuddin12, J. Fontcuberta4, T. Jungwirth3,7, R. Ramesh1,6
Nature Mater. 13 (2014) 367–374, doi: 10.1038/nmat3861

Ferromagnets are able to store digital information as "0" and "1" using different orientation of magnetic moments that could be pictured as small compasses (image a). This principle works in a broad variety of memory devices from kilobyte magnetic cards to terabyte hard disks. Ferromagnetic memory devices can't be placed near to another magnets or devices producing strong magnetict field – magnetic moments in memory would be reoriented resulting in loss of the stored information (image b). In collaboration with labs in Berkeley and Barcelona we demostrated that it is possible to use another type of materials for storing information, an antiferromagnet. Antiferromagnetic materials are magnetic within them but their microscopic magnetic moments from individual atoms alternates with opposite orientation (image c). Due to this antiparalel configurationof antiferromagnets (and unlike from the paralel configuration in ferromagnets) the information in antiferromagnetic memory devices is insensitive to outer magnetic fields (image d).

Ilustration shows principle of antiferromagnetic memory element.

1Department of Materials Science and Engineering and Department of Physics, University of California, Berkeley, California 94720, USA
2Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, 12116 Praha 2, Czech Republic
3Institute of Physics ASCR, v.v.i., Cukrovarnická 10, 162 53 Praha 6, Czech Republic
4Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, Campus UAB, Bellaterra E-08193, Spain
5Max Planck Institute of Microstructure Physics, Weinberg 2, Halle D-06120, Germany
6Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
7School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
8Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
9Institute of Physics ASCR, v.v.i., Na Slovance 2, 182 21 Praha 8, Czech Republic
10Institute of Physics of Materials ASCR, v.v.i., Zizkova 22, Brno 616 62, Czech Republic
11National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
12Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, California 94720, USA