Coupled multiferroic domain switching in the canted conical spin spiral system Mn<sub>2</sub>GeO<sub>4</sub>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 28580933.
- Also identified by DOI 10.1038/ncomms15457 and PMC identifier 5465321.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Despite remarkable progress in developing multifunctional materials, spin-driven ferroelectrics featuring both spontaneous magnetization and electric polarization are still rare. Among such ferromagnetic ferroelectrics are conical spin spiral magnets with a simultaneous reversal of magnetization and electric polarization that is still little understood. Such materials can feature various multiferroic domains that complicates their study. Here we study the multiferroic domains in ferromagnetic ferroelectric Mn<sub>2</sub>GeO<sub>4</sub> using neutron diffraction, and show that it features a double-Q conical magnetic structure that, apart from trivial 180<sup>o</sup> commensurate magnetic domains, can be described by ferromagnetic and ferroelectric domains only. We show unconventional magnetoelectric couplings such as the magnetic-field-driven reversal of ferroelectric polarization with no change of spin-helicity, and present a phenomenological theory that successfully explains the magnetoelectric coupling. Our measurements establish Mn<sub>2</sub>GeO<sub>4</sub> as a conceptually simple multiferroic in which the magnetic-field-driven flop of conical spin spirals leads to the simultaneous reversal of magnetization and electric polarization.