Theory of Ferromagnetism in Ca_1-xLa_xB_6
Abstract
Novel ferromagnetism in Ca_1-xLa_xB6 is studied in terms of the Ginzburg-Landau theory for excitonic order parameters, taking into account symmetry of the wavefunctions. We found that the minima of the free energy break both inversion and time-reversal symmetries, while the product of these two remains preserved. An important point is that this predicts the magnetoelectric effect; novel ferromagnetism in Ca_1-xLa_xB6 and that in powder or thin-film CaB6 can be attributed to this magnetoelectric effect. We note that this mechanism is different from other known scenarios based on exciton condensation. We also make a number of predictions on magnetic and optical properties, including the magneto-chiral effects.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2002
- Bibcode:
- 2002APS..MARX14008M