Dielectric properties and electrical switching behaviour of the spin-driven multiferroics
In the last decade various mechanisms for coupled polar and magnetic ordering, so called multiferroicity, were discovered. Especially in case of strong magnetoelectric coupling, multiferroic systems can pave the way for new generations of, e.g., sensors. Therefore, mechanisms for multiferroicity, e.g., electric-dipole-driven magnetism or charge-order driven ferroelectricity, and new multiferroic systems, e.g. artificial heterostructures, are in the scientific focus.
Dielectric spectroscopy and non-linear electrical measurements are powerful tools to analyze the electronic properties of multiferroic systems giving new insights into the underlying physics, which allows their optimization. Here, we thoroughly discuss the dielectric properties of one important multiferroic system. We address the question, if there is a new exotic high-temperature multiferroic phase in the spin-driven ferroelectric system LiCuVO4 extending its (H,T)-phase diagram to higher temperatures [1]. LiCuVO4 is also a prototypical example of a strong-coupled spin-spiral state with ferroelectric ordering below 2.5 K. This allows us to switch the polarization by an external magnetic field [2,3], which is a key result for the possible applicability of multiferroic systems.
[1] N. Büttgen et al., Phys. Rev. B 85, 214421 (2012).
[2] F. Schrettle, S. Krohns, P. Lunkenheimer, J. Hemberger, N. Büttgen, H.-A. Krug von Nidda, A.V. Prokofiev, A. Loidl, Phys. Rev. B 77, 144101 (2008).
[3] A. Ruff, S. Krohns, P. Lunkenheimer, A.V. Prokofiev, A. Loidl, J. Phys. Condens. Matter. 26, 485901 (2014).