Magnetic monopoles propagating in a magnetic material Discovery of the quantum dynamics of magnetic monopoles

© Kenta Kimura,
Schematic image of quantum dynamics of magnetic monopoles

Magnets are known to form a pair of north and south poles. However, recent theoretical work has revealed that magnetic monopoles, a magnet with only a north or south pole, can exist as elementary excitations in some special magnets. Particularly in a magnetic material known as spin ice, it has been experimentally confirmed that a magnetic point defect created by thermal fluctuations behaves as a magnetic monopole. However, the monopole in spin ice is only thermally-diffusive and freezes at low temperatures.

An experimental group at the Institute for Solid State Physics of the University of Tokyo, in cooperation with researchers at Nagoya University, Johns Hopkins University, and Oak Ridge National Laboratory, have developed a new spin ice material Pr2Zr2O7 and revealed the quantum dynamics associated with magnetic monopoles. This discovery indicates the coherent propagation of magnetic monopoles and it is a significant step deepening our understanding of magnetic monopoles in magnetic materials. Furthermore, the magnetic monopole found in this study may transfer spin information without using electric currents and thus it may open a new route to the development of further energy saving spintronics devices.

Press release (Japanese)

Paper

K. Kimura, S. Nakatsuji, J-J. Wen, C. Broholm, M. B. Stone, E. Nishibori, H. Sawa,
“Quantum fluctuations in spin-ice-like Pr₂Zr₂O₇”,
Nature Communications Online Edition: 2013/06/17 (Japan time), doi: 10.1038/ncomms2914.
Article link

Links

Institute for Solid State Physics

Division of New Materials Science

Nakatsuji Laboratory, Division of New Materials Science, Institute for Solid State Physics