Search for the Magnetic Monopole at a Magnetoelectric Surface

Quintin N. Meier, Michael Fechner, Tadasuke Nozaki, Masashi Sahashi, Zaher Salman, Thomas Prokscha, Andreas Suter, Peggy Schoenherr, Martin Lilienblum, Pavel Borisov, Igor E. Dzyaloshinskii, Manfred Fiebig (+2 others)
We show, by solving Maxwell's equations, that an electric charge on the surface of a slab of a linear magnetoelectric material generates an image magnetic monopole below the surface provided that the magnetoelectric has a diagonal component in its magnetoelectric response. The image monopole, in turn, generates an ideal monopolar magnetic field outside of the slab. Using realistic values of the electric and magnetic field susceptibilities, we calculate the magnitude of the effect for the
more » ... pical magnetoelectric material Cr 2 O 3 . We use low-energy muon spin rotation to measure the strength of the magnetic field generated by charged muons as a function of their distance from the surface of a Cr 2 O 3 film and show that the results are consistent with the existence of the monopole. We discuss other possible routes to detecting the monopolar field, and show that, while the predicted monopolar field generated by Cr 2 O 3 is above the detection limit for standard magnetic force microscopy, the detection of the field using this technique is prevented by surface charging effects.
doi:10.3929/ethz-b-000321160 fatcat:evs3ucraj5glho5sl5v2by2wtq