Dresden 2020 – scientific programme
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MA: Fachverband Magnetismus
MA 38: Multiferroics and Magnetoelectric Coupling II (joint session MA/KFM)
MA 38.3: Talk
Wednesday, March 18, 2020, 15:30–15:45, HSZ 401
Signatures of electric dipoles in zig-zag spin chain β-TeVO4 — Martina Dragičević1, Željko Rapljenović1, David Rivas Góngora1, Mirta Herak1, •Tomislav Ivek1, Matej Pregelj2, Andrej Zorko2, Helmuth Berger3, and Denis Arčon2,4 — 1Institute of Physics, Zagreb, Croatia — 2Jožef Stefan Institute, Ljubljana, Slovenia — 3Ecole polytechnique fédérale de Lausanne, Lausanne, Switzerland — 4Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia
Even though non-composite magnetoelectric materials appear to be rare, one promising way to achieve magnetoelectric effect is through spiral magnetic orders which can break the space inversion symmetry and allow electric dipoles to form. In this work we present the dielectric response of single crystal quasi-1D quantum magnet β-TeVO4 at low temperatures and in the presence of external magnetic field. This zig-zag spin chain system with frustrated anisotropic interactions has a complex phase diagram: at TN1 = 4.65 K the paramagnetic phase gives way to an incommensurate spin-density wave; below TN2 = 3.28 K a superposition of two spin-density waves is observed with differing wave vectors, the so-called spin stripe phase; finally, at the low temperature of TN3 = 2.28 K their two wave vectors coincide and a vector chiral ground state is established. Most interestingly, at TN3 there are tantalizing experimental indications of emergent electric dipoles. The magnetic phase diagram will be discussed in the context of dielectric properties and of ground state as a potentially multiferroic phase.