Chiral Order and Multiferroic Domain Relaxation in NaFeGe\(_2\)O\(_6\)

• Published in: arXiv.org
• Main Authors: Biesenkamp, S, Gorkov, D, Schmidt, W, Schmalzl, K, Sidis, Y, Becker, P, Bohatý, L, Braden, M
• Format: Paper
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 14.05.2021
• Subjects: Chirality; Crystallography; Domain walls; Dynamic structural analysis; Electric fields; Magnetic structure; Magnons; Multiferroic materials; Neutron scattering; Single crystals; Temperature dependence; Wave velocity
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2105.06875

The magnetic structure and the multiferroic relaxation dynamics of NaFeGe\(_2\)O\(_6\) were studied by neutron scattering on single crystals partially utilizing polarization analysis. In addition to the previously reported transitions, the incommensurate spiral ordering of Fe\(^{3+}\) moments in the \(ac\) plane develops an additional component along the crystallographic \(b\) direction below \(T\approx 5\text{ K}\), which coincides with a lock-in of the incommensurate modulation. The quasistatic control of the spin-spiral handedness, respectively of the vector chirality, by external electric fields proves the invertibility of multiferroic domains down to the lowest temperature. Time-resolved measurements of the multiferroic domain inversion in NaFeGe\(_2\)O\(_6\) reveal a simple temperature and electric-field dependence of the multiferroic relaxation that is well described by a combined Arrhenius-Merz relation, as it has been observed for TbMnO\(_3\). The maximum speed of domain wall motion is comparable to the spin wave velocity.