Multiferroicity in spin ice: Towards magnetic crystallography of Tb 2 Ti 2 O 7 in a field

L. D. C. Jaubert (1) , R. Moessner (2)

1 Okinawa Institute of Science and Technology
2 MPI-PKS - Max Planck Institute for the Physics of Complex Systems

We combine two aspects of magnetic frustration, multiferroicity and emergent quasiparticles in spin liquids, by studying magnetoelectric monopoles. Spin ice offers to couple these emergent topological defects to external fields, and to each other, in unusual ways, making it possible to lift the degeneracy underpinning the spin liquid and to potentially stabilize novel forms of charge crystals, opening the path to a “magnetic crystallography.” In developing the general phase diagram including nearest-neighbor coupling, Zeeman energy, and electric and magnetic dipolar interactions, we uncover the emergence of a bilayered crystal of singly charged monopoles, whose stability, remarkably, is strengthened by an external [110] magnetic field. Our theory is able to account for the ordering process of Tb2Ti2O7 in a large field for reasonably small electric energy scales.

Domaines: Mécanique statistique [cond-mat.stat-mech]

L. D. C. Jaubert, R. Moessner. Multiferroicity in spin ice: Towards magnetic crystallography of Tb 2 Ti 2 O 7 in a field. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2015, 91, pp.214422. ⟨10.1103/PhysRevB.91.214422⟩. ⟨hal-01542080⟩